Make AuthenticationDao suspensible

[TimoPtr]

Summary

After enabling StrictMode in #5483 I found out that we are doing many db calls on the main thread where we shouldn't. It most probably causes some ANR. This PR is related to the AuthenticationDao all the DAO methods should be marked as suspend.

Part of #5520

Checklist

• New or updated tests have been added to cover the changes following the testing guidelines.
• The code follows the project's code style and best_practices.
• The changes have been thoroughly tested, and edge cases have been considered.
• Changes are backward compatible whenever feasible. Any breaking changes are documented in the changelog for users and/or in the code for developers depending on the relevance.

[TimoPtr]

@dshokouhi @jpelgrom do you know a way to quickly test that it is not broken?

[jpelgrom]

Iframe in the dashboard which requires HTTP auth?