(cherry picked from commit 9acb145)

- Update GitLab to 12.3.4

- Update update.py to cope with the new upstream repository structure

- Refactor gitlab-shell to use buildGoPackage and bundlerEnv for
  dependencies

- Refactor gitlab-workhorse to use buildGoPackage for dependencies

- Make update.py able to update gitlab-shell and gitlab-workhorse
  dependencies

- Various fixes necessary for update to work

(cherry picked from commit f3eb063)

Split the remove-hardcoded-locations patch into two separate patches,
one for the ruby package and one for the go package. This is clearer
and results in fewer rebuilds.

(cherry picked from commit 09e657e)

Instead of extracting prebuilt assets from the debian build, build
them from the source. This should give faster package updates and
reduces the amount of data needed to be downloaded by more than 500MB.

(cherry picked from commit 59324d1)

GitLab recently restructured their repos; whereas previously they had
one gitlab-ce and one gitlab-ee repo, they're now one and the
same. All proprietary components are put into the ee subdirectory -
removing it gives us the foss / community version of GitLab. For more
info, see
https://about.gitlab.com/2019/02/21/merging-ce-and-ee-codebases/

This gives us the opportunity to simplify things quite a bit, since we
don't have to keep track of two separate versions of either the base
data or rubyEnv.

(cherry picked from commit afa3abf)

(cherry picked from commit 9be76d0)

(cherry picked from commit c115d4d)

Since the preStart script is no longer running in privileged mode, we
reassign the files in the state directory and its config subdirectory
to the user we're running as. This is done by splitting the preStart
script into a privileged and an unprivileged part where the privileged
part does the reassignment.

Also, delete the database.yml symlink if it exists, since we want to
create a real file in its place.

Fixes #68696.

(cherry picked from commit 0f8133d)

The initializers directory is populated with files from the gitlab
distribution on start, but old files will be left in the state folder
even if they're removed from the distribution, which can lead to
startup failures. Fix this by always purging the directory on start
before populating it.

(cherry picked from commit c6efa9f)

config.services.postgresql.package is only defined when the postgresql
service is activated, which means we fail to evaluate when
databaseCreateLocally == false. Fix this by using the default
postgresql package when the postgresql service is disabled.

(cherry picked from commit ec958d4)

Make sure that we don't create a database if we're not going to
connect to it. Also, fix the assertion that usernames be equal to only
trig when peer authentication is used (databaseHost == "").

(cherry picked from commit 58a7502)