Fix Detect Host Keys not working

Closes #56855

See merge request gitlab-org/gitlab-ce!24884

Merge branch '9558-alert-notification-not-working-for-managed-prometheus-installations' into 'master'

Resolve "Alert notification not working for managed Prometheus installations"

Closes #9558

See merge request gitlab-org/gitlab-ee!9402

accured -> occurred, as suggested in…

See merge request gitlab-org/gitlab-ce!23629

DB and model changes for Sentry project selection dropdown

See merge request gitlab-org/gitlab-ce!24677

Implement alerting setting model

See merge request gitlab-org/gitlab-ee!9334

Refactor helper in environments controller for clarity

See merge request gitlab-org/gitlab-ce!24781

Consume jobs from dead and retry queues

See merge request gitlab-org/gitlab-ce!24881

CE upstream - 2019-02-02 19:09 UTC

See merge request gitlab-org/gitlab-ee!9408

Use ECharts for metrics dashboard graphs

See merge request gitlab-org/gitlab-ce!24648

Fix template labels

Closes #55744

See merge request gitlab-org/gitlab-ce!24803

Resolve "Block emojis and symbol characters from user's full names"

Closes #50521

See merge request gitlab-org/gitlab-ce!24523

Backport of ee/9235: Add LDAP integration to smartcard authentication

See merge request gitlab-org/gitlab-ce!24704

Add LDAP integration to smartcard authentication

See merge request gitlab-org/gitlab-ee!9235

Fix ReturnInVoidContext rubocop offense

See merge request gitlab-org/gitlab-ce!24857

Update UI of admin appearance settings

See merge request gitlab-org/gitlab-ce!24685

Update UI of admin appearance settings (EE)

See merge request gitlab-org/gitlab-ee!9307

Renders new & edit feature flag page in Vue

See merge request gitlab-org/gitlab-ee!9228

Merge branch '19745-forms-with-task-lists-can-be-overwritten-when-editing-simultaneously' into 'master'

Forms with task lists can be overwritten when editing simultaneously

See merge request gitlab-org/gitlab-ce!23938

Merge branch 'ee-19745-forms-with-task-lists-can-be-overwritten-when-editing-simultaneously' into 'master'

EE port of task list improvements MR

See merge request gitlab-org/gitlab-ee!9365

Resolve "UI bug adding group members with lower permissions"

Closes #55098

See merge request gitlab-org/gitlab-ce!24820

Docs: corrects link

See merge request gitlab-org/gitlab-ce!24865

Docs: Fix some references to the mirroring doc

See merge request gitlab-org/gitlab-ce!24879

Docs: EE Port: Fix some references to the mirroring doc

See merge request gitlab-org/gitlab-ee!9406

publickeymustbechangedtoprivatekey.md

See merge request gitlab-org/gitlab-ce!24830

Docs: Fix link references for artifacts

See merge request gitlab-org/gitlab-ce!24843

EE Port: Docs: Fix link references for artifacts

See merge request gitlab-org/gitlab-ee!9384

It implements certificate matching using certificateExactMatch matching
rule defined in RFC4523.

Due to a change in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24245, the Detect
Host Key feature in the SSH mirroring stopped working.
`SshHostKey#primary_key` was being used instead of the hard-coded
`:id`. However, `SshHostKey#find_by` was expecting the symbolized `:id`
rather than the string `id`, so it could never find the host key it was
supposed to update.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/56855