Changed views to partials, created the repository view,
created a repository_helper to further aid the creation of variables
across different controllers

This makes dropdown to look according the dropdowns on the edit form. This options add a tick mark next to the selected option.

!581 has a lot of changes that would cause merge conflicts if not
properly backported to CE. This commit/MR serves as a better
foundation for gitlab-org/gitlab-ee!581.

= Changes =

1. Move from `has_one {merge,push}_access_level` to `has_many`, with the
   `length` of the association limited to `1`. This is _effectively_ a
   `has_one` association, but should cause less conflicts with EE, which
   is set to `has_many`. This has a number of related changes in the
   views, specs, and factories.

2. Make `gon` variable loading more consistent (with EE!581) in the
   `ProtectedBranchesController`. Also use `::` to prefix the
   `ProtectedBranches` services, because this is required in EE.

3. Extract a `ProtectedBranchAccess` concern from the two access level
   models. This concern only has a single `humanize` method here, but
   will have more methods in EE.

4. Add `form_errors` to the protected branches creation form. This is
   not strictly required for EE compatibility, but was an oversight
   nonetheless.

Since .panel-heading is a bit different from bootstrap, using .panel-title for h3 looks different.

So with this .panel-title will look good again inheriting custom properties our app sets for .panel-heading

Also updates protect branch list