Unify lib/api/merge_requests.rb between CE and EE

See merge request gitlab-org/gitlab-ee!4404

Docs guidelines: cherry-picking commits from CE to EE

See merge request gitlab-org/gitlab-ee!4729

Fixes broken link on gitlab-ci-yaml include documentation

See merge request gitlab-org/gitlab-ee!4856

Extract EE::API::JobArtifacts

See merge request gitlab-org/gitlab-ee!4854

Fixed IDE changed files not reseting after commit

Closes #5094

See merge request gitlab-org/gitlab-ee!4810

CE upstream - 2018-03-06 00:34 UTC

Closes gitaly#1054 et gitaly#1048

See merge request gitlab-org/gitlab-ee!4848

Move external files support from Premium to Starter

See merge request gitlab-org/gitlab-ee!4841

Port to EE: Reload stable object to prevent erase artifacts with old state

See merge request gitlab-org/gitlab-ee!4844

* ee/master:
  Add project export API
  Lock gRPC gem to 1.8
  Add spec
  Fix http_io to make it return path is nil
  Add find-sec-bugs in the list of tools for java SAST. Refs #4123
  Changes after review
  Fix broken empty tab state
  Manage empty states in Pipelines page Adds i18n Adds test
  Merge from CE

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/16973

Add project export API

See merge request gitlab-org/gitlab-ee!4851

Lock gRPC gem to 1.8

Closes gitaly#1059

See merge request gitlab-org/gitlab-ee!4828

Add find-sec-bugs in the list of tools for java SAST

See merge request gitlab-org/gitlab-ee!4845

Update Kubernetes CPU/Memory Prometheus queries

See merge request gitlab-org/gitlab-ee!4771

Fix http_io to make it return path is nil

Closes #5119

See merge request gitlab-org/gitlab-ee!4833

Port of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/15860

Given 1.9 has issues we're aware of, for now we're locking to 1.8.
Closes gitlab-org/gitaly#1059 and will probably be removed if 1.10 is
tested an deemed ok.

Port of 38587-pipelines-empty-state to EE

See merge request gitlab-org/gitlab-ee!4829