This will enable admins to identify who actually made the API request.

Relates to #36960

Include X-Content-Type-Options (XCTO) header into API responses

See merge request gitlab/gitlabhq!2211

(cherry picked from commit 6c818e77)

e087e075 Include X-Content-Type-Options (XCTO) header into API responses

Closes #36189

Signed-off-by: NRémy Coutable <remy@rymai.me>

- Declaring an endpoint's scopes in a `before` block has proved to be
  unreliable. For example, if we're accessing the `API::Users` endpoint - code
  in a `before` block in `API::API` wouldn't be able to see the scopes set in
  `API::Users` since the `API::API` `before` block runs first.

- This commit moves these declarations to the class level, since they don't need
  to change once set.

Restrict API X-Frame-Options to same origin

See merge request !2103

Ran:
 - git format-patch v9.2.2..v9.2.5 --stdout > patchfile.patch
 - git checkout -b 9-2-5-security-patch origin/v9.2.2
 - git apply patchfile.patch
 - git commit
 - [Got the sha ref for the commit]
 - git checkout -b upstream-9-2-security master
 - git cherry-pick <SHA of the patchfile commit>
 - [Resolved conflicts]
 - git cherry-pick --continue

Ran:
 - git format-patch v9.2.2..v9.2.5 --stdout > patchfile.patch
 - git checkout -b 9-2-5-security-patch origin/v9.2.2
 - git apply patchfile.patch
 - git commit
 - [Got the sha ref for the commit]
 - git checkout -b upstream-9-2-security master
 - git cherry-pick <SHA of the patchfile commit>
 - [Resolved conflicts]
 - git cherry-pick --continue

* Meld the following disparate endpoints:
 * `/projects/:id/events`
 * `/events`
 * `/users/:id/events`
+ Add result filtering to the above endpoints:
 * action
 * target_type
 * before and after dates

There was a race condition issue when the application was generating an
email and was using a language that was previously being used in other
request.

- As opposed to the issue `id` that was previously being used.
- This brings the API routes closer to the web interface's routes.
- This is specific to API v4.

Fixes gitlab-org/gitlab-ce#28515

[ci skip]