Rename `build_events` to `job_events`

Closes #31620

See merge request !11287

This reverts merge request !11287

Removed all the unnecessary include of `WaitForAjax` and `ApiHelpers` in the specs.
Removed unnecessary usage of `api:true`

This commit was about 6 commits before squashing, with the main goal to
make all tests green. Now, after pushing this commit we'll see what the
CI has to say about that.

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

Restore changes for api spec files

Fix error in rspec Users

Delete extra space Repositories-spec

The UI allows to define a token to validate payload on the target URL,
this patch adds the feature to the API.

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5620#note_13823349

Closes #20115

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15576

Signed-off-by: NJeroen van Baarsen <jeroenvanbaarsen@gmail.com>

* project_with_code -> project
* project -> ermpty_project
Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>