* docs - add information on upgrading to PostGIS 2.5.4

Upgrade instructions 2.1.5 to different versions of 2.5.4

* docs - upgrade to PostGIS 2.5.4 review comments

* docs - more review comment updates.
reorder upgrade sections.
clarify removing PostGIS package, is for removing the gppkg

* docs - minor edit

* docs - review updates - more emphasis on removing PostGIS from a database deleting objects.
-Create separate paragraph in Upgrading section.
-Add warning in Removing PostGIS section

* docs - minor review comment update

* small edits
Co-authored-by: NDavid Yozie <dyozie@pivotal.io>

* docs - clarify gpcopy supported greenplum versions

* use or later rather than +

* docs - add information on table rewrites when executing ALTER TABLE commands.

Information is in Notes section of ALTER TABLE.
Also, made some minor edits.

* docs - updates based on review comments.
-simplified table listing ALTER TABLE commands that perform table rewrites.
-add links to table rewrite information.

doc change for dev PR https://github.com/greenplum-db/gpdb/pull/10493

* docs - support proxies for GPDB interconnect

-New topic in Admin. Guide.
-New GUC gp_interconnect_proxy_addresses
-Updated GUC gp_interconnect_type - new value PROXY

Also added note to gpexpand documents - do no use proxy during expand.

* docs - review comment updates

* docs - review comment updates.
-update IC proxy example function
-other minor edits.

* docs - add not about running ic-proxy configuration function.

* docs - note how oss users get gpbackup

* small edit

Add information about the compression parameters used when
a column is added to an AOCO table.

* docs - update utility docs with IP/hostname information.

Add information to gpinitsystem, gpaddmirrors, and gpexpand ref. docs
--Information about using hostnames vs. IP addresses
--Information about configuring hosts that are configured with mulitple NICs

Also updated some examples in gpinitsystem

* docs - review comment updates. Add more information from dev.

* docs - change examples to show valid configurations that support failorver.
Also fix typos and minor edits.

* docs - updates based on review comments.

* docs - add information for SSL with standby master

--SSL file should not be in $MASTER_DATA_DIRECTORY

Also
--Add not about not using NULL ciphers
--Correct default directory for SSL files to $MASTER_DATA_DIRECTORY

* docs - review comment updates

* docs - gphdfs2pxf migration pxf supports avro compression

* missing plural

--Also, add some links to other topics.

* docs - add GUC -write_to_gpfdist_timeout

Add GUC and add link to GUC in gpfdist reference

* docs - correct default value 600 --> 300. Fix xref.

* Doc updates to cover packaging changes/additions for versions 7/6

* Removing nav link to non-default steps

* Add missing chown examples; add note about symbolic link update in upgrade procedure

* Typo fix

* docs - update pxf migration info and greenplum upgrade info

* post upgrade init not always required

* use procedure step name for xref

* forgot about this page - xref to pxf dita landing page

* fix some links

* xref to PXF packaging README on greenplum oss docs landing page

* redirect install topic to pxf README for oss docs

* pxf oss subnav includes only migration/upgrade topics

* next greenplum minor releases will include embedded pxf

* migrate topic - call pxf directly

* update upgrade subnav title

* use underscore in filename

* docs - add views pg_stat_all_tables and indexes

pg_stat_all_indexes
pg_stat_all_tables

Also add some statistics GUCs.
--track_activities
--track_counts

* docs - clarify seq_scan and idx_scan refer to the total number of scans from all segments

* docs - minor edits

* docs - update postGIS 2.5.4 docs

Updates for Greenplum PostGIS 2.5.4 v2

--Add list of PostGIS extensions
--Add support for PostGIS TIGER geocoder, address standardizer and address rules files.
--Update install/uninstall instructions to use CREATE EXTENSION command
--Remove postgis_manager.sh script
--Remove PostGIS Raster limitation.

* docs updated PostGIS 2.5.4 docs based on review comments.

* docs - removed postgis_raster extension.

* docs - review comment updates  -Added section for installing the PostGIS package
-Updated section on removing PostGIS package
-Fix typos.

* docs - updated platform requirements for PostGIS 2.5.4 v2
-also removed "beta" from GreenplumR

* clarifying pg_upgrade note

* graph edits

* graph analytics updates

* menu edits and code spacing

* graph further edits

* insert links for modules

* clarifying pg_upgrade note

* gpinitsystem -O clarification

* further reviews

* Update statement about mirroring recommendations & support

* Updates based on k8s feedback

Use guc gp_role only now and replace the functionality of guc gp_session_role with it
also. Previously we have both gucs. The difference of the two gucs are (copied
from code comment):

 * gp_session_role
 *
 * - does not affect the operation of the backend, and
 * - does not change during the lifetime of PostgreSQL session.
 *
 * gp_role
 *
 * - determines the operating role of the backend, and
 * - may be changed by a superuser via the SET command.

This is not friendly for coding. For example, You could find Gp_role and
Gp_session_role are set as GP_ROLE_DISPATCH on Postmaster & many aux processes
on all nodes (even QE nodes) in a cluster, so you can see that to differ from
QD postmaster and QE postmaster, current gpdb uses an additional -E option in
postmaster arguments. These makes developers confusing when writing role branch
related code given we have three related variables.  Also some related code is
even buggy now (e.g. 'set gp_role' even FATAL quits).

With this patch we just have gp_role now. Some changes which might be
interesting in the patch are:

1. For postmaster, we should specify '-c gp_role=' (e.g. via pg_ctl argument) to
   determine the role else we assume the utility role.

2. For stand-alone backend, utility role is enforced (no need to specify by
   users).

3. Could still connect QE/QD nodes using utility mode with PGOPTIONS, etc as
   before.

4. Remove the '-E' gpdb hacking and align the '-E' usage with upstream.

5. Move pm_launch_walreceiver out of the fts related shmem given the later is
   not used on QE.
Reviewed-by: NBhuvnesh Chaudhary <bchaudhary@pivotal.io>
Reviewed-by: NGang Xiong <gxiong@pivotal.io>
Reviewed-by: NHao Wu <gfphoenix78@gmail.com>
Reviewed-by: NYandong Yao <yyao@pivotal.io>