Fixed issues pointed out.

ref)
https://docs.gitlab.com/omnibus/settings/nginx.html#configuring-gitlab-trusted_proxies-and-the-nginx-real_ip-module

So as to be consistent with what is set in Omnibus

Revert "Store pages in shared/pages/fqdn/fqdn/public or shared/pages/fqdn/subpath/public - makes it simpler to implement CNAMEs in future"

This reverts commit 86a2a78f0d13a678899460638add6b862059433e.

Store pages in shared/pages/fqdn/fqdn/public or shared/pages/fqdn/subpath/public - makes it simpler to implement CNAMEs in future

- The pages are created when build artifacts for `pages` job are uploaded
- Pages serve the content under: http://group.pages.domain.com/project
- Pages can be used to serve the group page, special project named as host: group.pages.domain.com
- User can provide own 403 and 404 error pages by creating 403.html and 404.html in group page project
- Pages can be explicitly removed from the project by clicking Remove Pages in Project Settings
- The size of pages is limited by Application Setting: max pages size, which limits the maximum size of unpacked archive (default: 100MB)
- The public/ is extracted from artifacts and content is served as static pages
- Pages asynchronous worker use `dd` to limit the unpacked tar size
- Pages needs to be explicitly enabled and domain needs to be specified in gitlab.yml
- Pages are part of backups
- Pages notify the deployment status using Commit Status API
- Pages use a new sidekiq queue: pages
- Pages use a separate nginx config which needs to be explicitly added

This reverts commit 47b5b441.

See https://gitlab.com/gitlab-org/gitlab-ce/issues/17877#note_13488047

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/17877 .

This change adds 'defense in depth' against 'Host' HTTP header
injection. It affects normal users in the following way. Suppose your
GitLab server has IP address 1.2.3.4 and hostname gitlab.example.com.
Currently, if you enter 1.2.3.4 in your browser, you get redirected to
1.2.3.4/users/sign_in. After this change, you get redirected from
1.2.3.4 to gitlab.example.com/users/sign_in. This is because the
address you typed in the address bar of your browser ('1.2.3.4'),
which gets stored in the 'Host' header, is now being overwritten to
'gitlab.example.com' in NGINX.

In this change we also make NGINX clear the 'X-Forwarded-Host' header
because Ruby on Rails also uses that header the same wayas the 'Host'
header.

We think that for most GitLab servers this is the right behavior, and
if not then administrators can change this behavior themselves at the
NGINX level.

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

[ci skip]

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15398

Otherwise this might 'hide' problems
https://github.com/gitlabhq/gitlabhq/issues/10053#issuecomment-188919319

[ci skip]

It turns out that if we do not the declaration from
"location /" wins.

Limiting, if any, should happen in gitlab-workhorse.

- Offloads uploading to GitLab Workhorse
- Use /authorize request for fast uploading
- Added backup recipes for artifacts
- Support download acceleration using X-Sendfile

Users are allowed to supply namespace%2Fproject instead of a numeric ID

This change relies on changes in gitlab_git and gitlab-git-http-server.

Before this change NGINX would convert a chunked HTTP POST (e.g.
git push) into a HTTP 1.0 single large POST. This creates an
unnecessary delay, and it creates unnecessary memory pressure on
gitlab-git-http-server.

For the response ('proxy_buffering') I am less sure that NGINX 's
buffering behavior is harmful, but it still makes more sense to me
not to interfere with gitlab-git-http-server (and the Golang net/http
server).