Drop config.get_config backwards compatibility shim

[mirekdlugosz]

Remove old backwards compatibility shim and using configuration as dictionary, embrace strongly-typed settings.

The main change is that API client can be provided settings objects as parameter. This greatly simplifies unit tests.

Also - configuration fields like hostname are required and this condition is checked by pydantic when creating the object. We don't need to check if hostname is available when constructing the client - if we get that far, it means we do have hostname.

I took a bit of debt in camayoc/tests/qpc/api/v1/utils.py - the function in question is effectively replaced by data provider, but is never invoked for now as tests that use it are marked as skipped.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 83.33333% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 77.24%. Comparing base (c6771b7) to head (e1f3e4b).

Files	Patch %	Lines
camayoc/api.py	77.77%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #492 +/- ## ========================================== - Coverage 77.55% 77.24% -0.31% ========================================== Files 7 7 Lines 637 624 -13 ========================================== - Hits 494 482 -12 + Misses 143 142 -1 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.