ORCA Explain plans will now contain:
`Optimizer: Pivotal Optimizer (GPORCA) version 3.35.0`

instead of:
`Optimizer: PQO version 3.35.0`

Authored-by: Chris Hajas chajas@pivotal.io

As we merge with upstream and by that keep refining the Postgres
planner, legacy planner is no longer a suitable name. This changes
all variations of the spelling (legacy planner, legacy optimizer,
legacy query optimizer etc) to say "Postgres" rather than "legacy".
Reviewed-by: NVenkatesh Raghavan <vraghavan@pivotal.io>
Reviewed-by: NDavid Yozie <dyozie@pivotal.io>
Reviewed-by: NGeorgios Kokolatos <gkokolatos@pivotal.io>

We used to call some node types different names in EXPLAIN output,
depending on whether the plan was generated by ORCA or the Postgres
planner. Also, a Bitmap Heap Scan used to be called differently, when the
table was an AO or AOCS table, but only in planner-generated plans. There
was some historical justification for this, because they used to
be different executor node types, but commit db516347 removed last such
differences.

Full list of renames:

Table Scan -> Seq Scan
Append-only Scan -> Seq Scan
Append-only Columnar Scan -> Seq Scan
Dynamic Table Scan -> Dynamic Seq Scan
Bitmap Table Scan -> Bitmap Heap Scan
Bitmap Append-Only Row-Oriented Scan -> Bitmap Heap Scan
Bitmap Append-Only Column-Oriented Scan -> Bitmap Heap Scan
Dynamic Bitmap Table Scan -> Dynamic Bitmap Heap Scan

* rewording/conditionalizing more Pivotal-specific info

* conditionalizing/editing/or getting rid of more Pivotal-specific references and info

* removing incorrect warnings stating that GPORCA is not compatible with gpperfmon db

* doc changes to support GPORCA on by default

* moving linux kerberos client instructions to dedicated topic, and placing it parallel with existing windows topic

* removing map and dita files for connectivity package, which is no longer provided

* removing more references to connectivity packages; conditionalizing postgres odbc/jdbc vs datadirect drivers for oss/pivotal audiences

* adding .ditaval for handling pivotal conditions; [ci skip]

* relocating pivotal ditaval

* adding .ditaval for handling pivotal conditions; [ci skip]

* relocating pivotal ditaval

* removing/fixing old references to 4.3 version

* removing pgcrypto.fips mentions

* small fix to version format

* removing 'orca' from package version strings

* changing rhel5 to rhel6 in example version strings

* updating adminguide source with most recent 4.3.x work

* updating reference manual with most recent 4.3.x work

* updating utility guide with most recent 4.3.x changes

* updating client tools guide with most recent 4.3.x changes

* adding new file for client tools

* updating map files with most recent 4.3.x changes

* updating map files with most recent 4.3.x changes

* Revert "updating map files with most recent 4.3.x changes"

This reverts commit d7570343c17a126b4d11eaee3870ad6daa36966f.

* Revert "updating map files with most recent 4.3.x changes"

This reverts commit d7570343c17a126b4d11eaee3870ad6daa36966f.

* updating ditamaps with latest 4.3.x changes

* updating ditamaps with latest 4.3.x changes