[API] Fix URLs in the 'Link' header for 'GET /projects/:id/repository/contributors' when no value is passed for 'order_by' or 'sort'

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

Allows ordering in GET api/v4/projects/:project_id/repository/contributors
through `order_by` and `sort` params.
The available `order_by` options are: name|email|commits.
The available `sort` options are: asc|desc.

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

Remove unecessary endpoint from repository, add compatibility endpoints for v3 and several improvements

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

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

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

Restore changes for api spec files

Fix error in rspec Users

Delete extra space Repositories-spec

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

Closes #3311

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

Create RepoTag Grape entity and present it when doing stuff with tags via API. Update API doc for repositories. Add tag message to tag list page in UI. Update Changelog. Update spec to set .gitconfig identity, required for annotated tags.

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

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

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

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

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

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

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

Added annotated tags.  Updated tag haml file and call to gitlab-shell.  Updated API for annotated tags.  Added tests for API.  Strip leading/trailing whitespace from message, if present.  Update CHANGELOG.

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