Pagination for groups management page (BB-13735)

If you go to https://bitbucket.org/account/user/some_username/groups/ there is no pagination there for the groups that are added. On a paid account where we need to create at least one group per repo (i.e. project1-developers, project2-developers, etc.) this page got huge pretty quickly and now it's really hard to manage.

This needs to have some kind of pagination so that not all groups are all on the same page. Even better the overview page should have just the group names (searchable) and when you click on a group you go to a page where you manage this group's permissions and members.