Remove unused .contributed-projects class

While working on #13401 and trying to add a new tab to the user profile
page, I came across this. I noticed that the `contributed-projects`
class was only being used in order to select the div in the tests. For
consistency with the other tabs, I decided to remove this class and use
the div's id for the selector.

See merge request !3945

Use Rugged's TagCollection#create instead of gitlab-shell's Repository#add_tag for better performance

This was originally opened at !1757 by @pcarranza but I changed it to use Rugged instead of gitlab_git, following @DouweM's request.

Once this is merged, https://gitlab.com/gitlab-org/gitlab-shell/merge_requests/26 will be mergeable too.

See merge request !3745

Fix typo in user steps feature file

Just came across a typo in the user steps file.

See merge request !3943

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

Project webhooks updated UI

Closes #13993 

![Screen_Shot_2016-04-26_at_10.55.52](/uploads/684f79be18f8a69e9b5cbcca2c9b20e8/Screen_Shot_2016-04-26_at_10.55.52.png)

![Screen_Shot_2016-04-26_at_10.55.37](/uploads/9b9f3a8a243dec955f23967e20ec514f/Screen_Shot_2016-04-26_at_10.55.37.png)

See merge request !3922

Project deploy keys updated UI

Closes #13992

See merge request !3912

While working on #13401 and trying to add a new tab to the user profile
page, I came across this. I noticed that the `contributed-projects`
class was only being used in order to select the div in the tests. For
consistency with the other tabs, I decided to remove this class and use
the div's id for the selector.

[ci skip]