Update postgresql_user resource to allow different helpers

Closes #2348

See merge request !1561

Adding pgbouncer as EE specific dependency

See merge request !1345

Add a missing symlink for /opt/gitlab/init/sshd to make `gitlab-ctl stop` work in Docker

Closes gitlab-ee#2406

See merge request !1556

Update Matermost configuration options

See merge request !1558

Updating GitLab Mattermost to 3.9 for GitLab 9.2 release

See merge request !1552

Rename Trigger schedule to Pipeline Schedule

See merge request !1546

Adding `bin/compile` to gitlab-shell build steps

Closes #2304

See merge request !1554

Improve `gitlab-ctl replicate-geo-database` error messages

Closes gitlab-ee#2176

See merge request !1557

Re-apply workaround for Kubernetes 1.6 auth

Closes #2343

See merge request !1550

Allow setting `usage_ping_enabled` in `gitlab.rb`

See merge request !1543

Build Python with libedit

See merge request !1565

Registry aws go 1 8 fix

Closes #2350

See merge request !1563

Add external database config to gitlab-monitor

Closes #2288

See merge request !1529

Merge branch '2329-pg-insufficientprivilege-error-when-starting-gitlab-build-failed-15823054' into 'master'

Removing unless clause on postgresql extension enabling

Closes #2329 and #2302

See merge request !1538

Refactor Prometheus config generator

See merge request !1467

Add a link out to our kubernetes helm docs

See merge request !1541

Create a manual trigger to build package from .com repo also

Closes #2330

See merge request !1539

Use a YAML generator instead of a hand-crafted Chef template.
* Avoids invalid YAML syntax.
* Allows exporter recipes to self-register their scrape configs.
* Allows for easier extensions to the existing configs.
* Minor hack to avoid Chef's attribute magic[0].

[0]: https://tickets.opscode.com/browse/CHEF-3953

This reverts merge request !1527