Big rework of asyncio.tasks, abort handling and general stability improvements

[JulianFP]

Note: This increases the minimal required Python version

• Switch to asyncio TaskGroups
• Start all tasks from single place and keep them running, communicate through asyncio Synchronization Primitives
• add signal to stop processing thread, use this when application exits or when job is aborted
• better logging
• more checks and stability

Fixes #20

Partially implements #16

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (42fcf50) to head (e4dc9ba). Report is 8 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #22 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 1 1 Lines 2 2 ========================================= Hits 2 2 ```

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