Improve test cases, config settings, also show SSH config settings on admin config panel.

Remove the possibility of using email as user name when user actually push
through combination of email and password with HTTP.

Also refactor update action function to replcae tons of arguments with
single PushUpdateOptions struct.
And define the user who pushes code as pusher, therefore variable names shouldn't
be confusing any more.

Remote repository path is renamed but does not delete
outdated local copy which still has old repository path
as remote.

- update required version of git-module for #2373

- User profile un/follow
- List user's followers/following

The reasoning for that is in the previous commit.