Introduce ServerSessionManager to handle auth and session state

[TimoPtr]

Summary

Checklist

I decided to split the auth/session management used in the WebView in a dedicated class to avoid creating a giant ViewModel. The idea is to have things related in the same manager and injected into the viewModel.

• 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.

Any other notes

[github-actions]

Test Results

  146 files  + 1    146 suites  +1   8m 47s ⏱️ -6s
1 210 tests +10  1 210 ✅ +10  0 💤 ±0  0 ❌ ±0 
1 228 runs  +10  1 228 ✅ +10  0 💤 ±0  0 ❌ ±0 

Results for commit 367179b. ± Comparison against base commit c2e424c.

♻️ This comment has been updated with latest results.