Add an Organization manager by username

[marla-singer]

Closes #3344

Developer checklist

This checklist is to be completed by the PR developer:

• Alternative solutions were compared/discussed before writing code
  • trade-offs with this solution are considered acceptable
• Code in this PR adheres to the project styleguide
• This pull request does not decrease project test coverage
• If the code changes existing database collection(s), migration has been written
• If UI texts are added or changed, all texts are internationalized

Reviewer checklist

Reviewed by: @username1

This list is to be completed by the pull request reviewer:

• Code works as described/expected
• Code seems to be error free
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[matleppa]

Functionality as expected.
However, we should unify the UIs of "Authorized users for API" and "Organization managers", because in both places a similar functionality is performed.

Remake UI of "Organization manager" to be similar as the UI of "Authorized users for API".

• first is list of managers
• below list is input field for new manager
• Add button is below input field with text "Add new manager" and similar icon (fa fa-user) as in Authorized users.

[marla-singer]

we should unify the UIs of "Authorized users for API" and "Organization managers", because in both places a similar functionality is performed.

Yes, UI the same but the value of User ID is inserted in the different collections 🤷‍♀️
About the second point, will remake

[matleppa]

OK, I see, that I could have written more specific what I meant.

However, we should unify the UIs of "Authorized users for API" and "Organization managers",
-->
However, we should unify the look and feel of UIs of "Authorized users for API" and "Organization managers",

So, yes, the only goal is that the UIs are similar in both places.

[marla-singer]

@matleppa Made UI changes