added support for rsyncable backups to CNG

Closes gitlab-org/charts/gitlab#1584

See merge request gitlab-org/build/CNG!264

Update dev/omnibus-config with gitlab-exporter rename

See merge request gitlab-org/build/CNG!259

backup-utility: validate cli arguments

Closes gitlab-org/charts/gitlab#1587

See merge request gitlab-org/build/CNG!266

* the object-storage-backup utility now checks for the GZIP_RSYNCABLE
  environment variable
* the backup-utility script allows to enable rsyncable with a flag
rsyncable support for object storage and binary

fixes gitlab-org/charts/gitlab#1584

backup-utility: improved and unified help message

See merge request gitlab-org/build/CNG!267

* unified casing
* simplified help
* added information about timestamp meaning and backup usage
* added information about supported URL formats

backup-utility now exists with return code 1 for invalid arguments.

fixes gitlab-org/charts/gitlab#1587

Change references to gitlab-ce and gitlab-ee projects to gitlab-foss and gitlab

Closes gitlab-org/charts/gitlab#1516

See merge request gitlab-org/build/CNG!265

Signed-off-by: Balasankar "Balu" C <balasankar@gitlab.com>

Update https://gitlab.com/gitlab-org/gitlab-exporter.git in dependencies_io/git_repos.yml from v5.0.0 to v5.0.1

See merge request gitlab-org/build/CNG!261

gitlab elasticsearch indexer to 1.3.0

See merge request gitlab-org/build/CNG!263

Update gitlab-elasticsearch-indexer to v1.3.0 within CNG, thus charts.

Relates to https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/3587

certificates: check for contents before rm of certs

See merge request gitlab-org/build/CNG!262

Check that there are any contents within /etc/ssl/certs prior
to the `rm -r` call. This removes a spurious, known warning that
the directory is empty, and there is nothing to remove.

Relates to https://gitlab.com/gitlab-org/charts/gitlab/issues/1534

Force unicorn, sidekiq and task-runner images build when 'FORCE_RAILS_IMAGE_BUILDS=true'

See merge request gitlab-org/build/CNG!260

Add gcc to shell build

See merge request gitlab-org/build/CNG!255

Match GitLab Omnibus Git config parameters

Closes charts/gitlab#1109

See merge request gitlab-org/build/CNG!257

Signed-off-by: Rémy Coutable <remy@rymai.me>

# Conflicts:
#   gitlab-shell/Dockerfile

Rename gitlab-monitor to gitlab_exporter

See merge request gitlab-org/build/CNG!252

This change does a number of things:

* Hides internal GitLab references (speeding up clones)
* Enables push options
* Limits number of pack threads to 1 (may save CPU/memory but slow large packs)

Add gcc to the gitlab-shell build deps

See merge request gitlab-org/build/CNG!256

To fix broken master

Now that shell is build with gomod, additional dependencies are needed

Add variable to disable docker build cache

See merge request gitlab-org/build/CNG!254

This reverts commit 8580c0960c8d83209dea703abc7ab9ab95877274.