Shrink the compatibility module and remove Python <3.7 support

[alfawal]

Proposed Changes

Reducing the usage of the pika.compat usage. It's really depressing for a first-time contributor to see Python 2 being used nowadays.

I believe/hope that these changes will encourage more people to contribute!

Types of Changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes issue #NNNN)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (correction or otherwise)
• Cosmetics (whitespace, appearance)

Checklist

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creating the PR. If you're unsure about any of them, don't hesitate to
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mailing list. We're here to help! This is simply a reminder of what we
are going to look for before merging your code.

• I have read the CONTRIBUTING.md document
• All tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further Comments

On the consistency side. I believe that this repository should:

• Add pre-commit config and inform the contributors to use it. The pre-commit config:
  • Use black as its formatter.
  • Use isort as its imports reordering handler.
  • (Optional) Use items from ruff.
  • (Optional) Use pydocstyle for docstrings with the Google style.
  • etc.
• Do an initial run with the pre-commit on all files.

[alfawal]

What is the status of the file utils/codegen.py? it runs on Python 2 only, should I remove it? is it just a normal file deletion or is there anything that I have to do?

[lukebakken]

Thanks for this contribution. Please note that these changes have broken the test suites! I will leave this PR as a draft until the tests are fixed. Thanks.