Fix "NameError: uninitialized constant Rack::Proxy" in production environment

See merge request !1168

Port "Integrate webpack for frontend asset compilation" to EE

See merge request !1138

* master: (54 commits)
  Move project services to new location under Integrations
  Move webhooks to new a location under Integrations
  Fix documentation link in doc/user/project/pages/index.md
  Fixed merge request widget tests
  Small documentation changes and fixes for Geo
  Remove ‘EE-specific’ comments related to Pages feature
  Update specs with new method signatures
  rm_tag now takes a user argument
  Use GitOperationService instead
  Merge remote-tracking branch 'ce/fix-git-hooks-when-creating-file' into master-ce
  Mentioned pages to CE port in project/pages/index.md
  Fixed merge request environment not displaying
  Update guidance on handling shared secrets in HA setup
  Pull EE specific Gitlab::Auth code in to its own module
  Use `add_$role` helper in snippets specs
  Check public snippets for spam
  Keep snippet visibility on error
  Add info on using both push/pull repository mirroring
  Properly read approvalPending from dataset.
  Fix data attr spacing.
  ...

Refactor integrations page documentation

See merge request !1165

Fix documentation missing link in doc/user/project/pages/index.md

See merge request !1164

Minor updates to EE after porting pages to CE

See merge request !1156

Geo: Small documentation changes and fixes

See merge request !1158

Fixed merge request environment not displaying

Closes gitlab-ce#27080

See merge request !1154

Use delete_all in the gitlab:elastic:clear_index_status rake task

See merge request !1143

Pull EE specific Gitlab::Auth code in to its own module

See merge request !1112

Git operations cleanup

See merge request !1151

* ce/fix-git-hooks-when-creating-file: (78 commits)
  Make sure different project gets a merge request
  Try to check if branch diverged explicitly
  We don't care about the return value now
  Make GitHooksService#execute return block value
  Use commit rather than branch, and rename to avoid confusion
  @tree_edit_project is no longer used
  Fix renaming
  Rename from base to start because base could mean merge base
  Detect if we really want a new merge request properly
  Properly fix the edge case!
  Rename source to base to avoid confusion from MR
  Don't set invalid @mr_source_branch when create_merge_request?
  Prefer leading dots over trailing dots
  Fix for initial commit and remove unneeded args
  Just trust set_commit_variables to set everything!
  Prefer leading dots over trailing dots
  Merge request terms are reversed for GitOperationService
  I think I am really confused, should be @tree_edit_project
  Remove tag with git hooks
  Introduce Repository#with_repo_branch_commit
  ...

Add username and password to Jenkins hook url

Closes #804

See merge request !1035

Allow squashing MRs

Closes #150

See merge request !1024

Update guidance on handling shared secrets in HA setup

See merge request !1152

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/27080

Snippet spam EE

See merge request !1148

Only a tiny portion of code in EE for Gitlab::Auth was different
from CE. This had the potential to result in merge conflicts.
Now, it's moved in to its own EE module and is prepended into the
Gitlab::Auth class.