Add max queue size functionality to CoroQueue and related components

[phettberg]

• Introduced MaxQueueException for handling queue size limits.
• Updated CoroQueue to accept max_queue_size parameter.
• Modified MapAsync and SinkAsync to support max_queue_size.
• Added tests for queue size threshold behavior.

[phettberg]

@flofeurstein, could you please already review? I'll fix the CI faults later.
@semiversus, how important is Python 3.8 support to you?

[semiversus]

Python 3.8 and Python 3.9 are end of life, so you can drop the support of them.

[flofeurstein]

Good job!

[phettberg]

• VirtualEventLoop had compatibility issues with newer Python versions - replaced it with async-solipsism
• pylama can't execute with Python 3.12, and they just won't fix it: Fixes to work with Python 3.12+ klen/pylama#254
• flake8 has compatibility issues with Python 3.14. When using the newest flake8, it'll throw a lot of errors as new rules were added
• I dropped pylama and flake8 and replaced them with ruff. However, I can't really replace the checks 1:1, but I've tried the best I could. This is the current rule set:

# pycodestyle (E, W)
# mccabe (C90)
# flake8-bugbear (B)
# flake8-async (ASYNC)
# flake8-builtins (A)
# flake8-annotations (ANN) not used
# flake8-quotes (Q) not used
# pylint (PLC, PLE, PLR, PLW) not used
# ...
[tool.ruff.lint]
select = ["E", "W", "C90", "A", "B", "ASYNC"]

[tool.ruff.lint.flake8-quotes]
inline-quotes = "single"

• I did not try to fix code style or other issues by more use of linting or style checks; I just don't have the time. Furthermore, it's an act, do decide, what you want to check anyway.