Admin Area Geo improvements and refactoring

Description

In https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6452 we identified many different ways we can improve our code base through some refactor work:

• https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7395 Move Geo specific controllers in ee/admin to ee/admin/geo - https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6452#note_91412831 and https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6452#note_91412774
• gitlab-org/gitlab-ce!21787 : Refactor app/helpers/tab_helper.rb and app/views/layouts/nav/sidebar/_admin.html.haml to take namespace into consideration so we don't break navigation because two controllers has the same name in different namespaces
• Implement Design Proposal 1.
  • All tab https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7745
  • Search field https://gitlab.com/gitlab-org/gitlab-ee/issues/8121
• Implement Design Proposal 2. https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7512
• Implement Design Proposal 3. https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7789

Design proposals

1. Add an All tab with filtering mechanisms so we can search for a specific project or namespace (let's base on Admin > Projects search capabilities and adapt to this usecase), and make it the initial tab https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6452#note_92825966

Geo Notes/Project All tab

2. Adding link to Secondary Geo Nodes > Projects from from Admin > Geo Nodes on Primary via "Open projects" button in Secondary panels, see: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6452#note_89426661.

Open projects link on Primary

3. Admin > Projects > Project should have a block with similar synchronization information from Admin > Geo nodes > Projects when in a secondary node. https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6452#note_92822911

In sync	Pending	Failed