Review User/Manage menus with the aim to merge them in one

[allyoucanmap]

Description

We would like to merge the existing manager menu and login menu in a single dropdown:

• admin user
  

• normal user
  

Expected changes

• deprecate and remove ManagerMenu from localConfing.json and jsdoc
• Merge the logic from ManagerMenu inside the Login plugin allowing the injection of menu items from containers (see current MangerMenu logic)
• Evaluate a refactor of Login dropdown component from class to function removing also unused logic (eg. unsaved changes because already managed by save plugin)

What kind of improvement you want to add? (check one with "x", remove the others)

• Minor changes to existing features

Other useful information