feat(central): remove and enable/disable users via admin ui

[MaxPostema]

fixes: #3981

What are the main changes you did:

• remove user button
• enable and disable user accounts toggle

how to test:

• Go to: apps/central/#/admin/users
• create a user / remove users
• try to disable an user and login

todo:

• updated docs in case of new feature
• added/updated tests
• added/updated testplan to include a test for this fix, including ref to bug using # notation

Todo:

• combine removeUser and deleteUser?
• backend and frontend should not be able to disable "anonymous and admin"
• test coverage

[dtroelofsprins]

Did a functional test:

• I like the option to disable a user, when checking the user list it however seems a bit as if all users are disabled and the disabled ones are valid (looking at the sign of the person
  , but when hoovering over it is already clearly indicated => and also the values in the enabled column are clear enough.
• Deleting a user works fine, however, when it's in a member list in a schema it does not get removed there => which makes me wonder if it's really removed from the backend as I would think that the "userlist" in admin would be the main source?

[mswertz]

nice.
should not be able to disable anonymous
should have more test coverage?

[sonarcloud]

Quality Gate passed

Issues
11 New issues
0 Accepted issues

Measures
0 Security Hotspots
80.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud