Fixes and enhancements for Geo admin dashboard

Closes #4658, #4864, and #4493

See merge request gitlab-org/gitlab-ee!4536

Add labels support to Epics

Closes #3727 and #4032

See merge request gitlab-org/gitlab-ee!4773

Resolve "Repository mirroring should notify when failed"

Closes #1123

See merge request gitlab-org/gitlab-ee!4699

Port to EE "Add archive feature to trace"

See merge request gitlab-org/gitlab-ee!4776

EE PORT Bring one group issue board to CE

See merge request gitlab-org/gitlab-ee!4606

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

Integrate two workers into one ArchiveTraceWorker with pipeline_background queue. This queue takes loqer precedence than pipeline_default.

commit 8862cc2b083f59c0a59a2175b047c6b999ac38a7
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Thu Mar 1 18:01:55 2018 +0900

    Change the place of definition of object_storage:archive_legacy_trace

commit 51b26252ff5462c604d852bce9953cd381dcf218
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Thu Mar 1 17:49:37 2018 +0900

    Add object_storage queue to sidekiq_queues.ym. and correct queue name in all_queues.yml.

commit 1313ea164cd59992a469983f8579fe4e2a06e2d8
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Thu Mar 1 17:45:14 2018 +0900

    Fix spec failure on mysql because it can not store long traces

commit d1ba3523139ead0ca7a376c962fd1d7725bf1397
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Thu Mar 1 17:38:44 2018 +0900

    Fix static analysys

commit 9f8c8f9c6bb42c5601c4c15b601256e988871909
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Wed Feb 28 18:48:08 2018 +0900

    Add spec for workers

commit a34a06fbcc1d14a238b3a0b83e631ac714d8acb2
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Wed Feb 28 18:43:35 2018 +0900

    Add ObjectStorageQueue concern and test

commit 4203125467f12f32982c454ea50483ad9c04ac62
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Wed Feb 28 18:43:19 2018 +0900

    Fix rake task to use corrrect SQL

commit 0fb390a4467f868f9c9d9f999589aebeff1e7bec
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Wed Feb 28 18:14:41 2018 +0900

    Raise an error if conditions are not fulfilled in archive method

commit 87177b4d2c73e63dd4795f3375374dd3ae311c00
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Wed Feb 28 17:29:24 2018 +0900

    Add changelog

commit 267e1a95fc49f9b926925b3bf03e403f6a5a3dd9
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Wed Feb 28 03:44:13 2018 +0900

    Add soec for achevie! method. Fixed the method

commit d13208bcd48f701df1e016ea11d7e140b08edafd
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Wed Feb 28 01:24:23 2018 +0900

    Use find_in_batches for rake task

commit 9362c06bd0fea047be7e050937b4cf3c7caebfdb
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Wed Feb 28 01:24:01 2018 +0900

    Add object_storage queue

commit 8b2d135da2803f89505119a9c2a72b2c50b55396
Author: Shinya Maeda <shinya@gitlab.com>
Date:   Mon Feb 26 23:06:04 2018 +0900

    Add rake task. Adopt the latest fix. Drop CreateTraceArtifactService

commit 8705cd63d1e43039b3e3a2f6d6ecf3fdbe95f0ee
Author: Kamil Trzciński <ayufan@ayufan.eu>
Date:   Fri Feb 23 13:08:38 2018 +0100

    Proper fix for artifacts trace migration which is fully safe

Fixed IDE changed files not reseting after commit

Closes #5094

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