Python 3.9 - 3.12 support + requested fixes

[mephenor]

Included in this PR:

• Reverted some code changes to restore a Python 3.9 compatible state
• Moved devcontainer and Dockerfile back to Python 3.9
• Added tox for Python 3.9 - 3.12 testing
• Replaced distutils.utils strtobool with a simple in module implementation
• Moved service-commons api requirements into dev dependencies as it's only needed for testing
• Updated dependencies - let me know if the lower bound for hexkit needs to be higher

Please check if the Python base image version for the Dockerfile is the correct one.

As the 3.9 compatibility changes also needed some script files to be changed, there are a few things in the static_files_ignore now which need to be manually updated.

[coveralls]

Pull Request Test Coverage Report for Build 9875834914

Details

• 17 of 24 (70.83%) changed or added relevant lines in 10 files are covered.
• 5 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.6%) to 72.453%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/ghga_connector/core/exceptions.py	0	1	0.0%
src/ghga_connector/core/uploading/api_calls.py	3	5	60.0%
src/ghga_connector/core/uploading/uploader.py	1	5	20.0%

Files with Coverage Reduction	New Missed Lines	%
src/ghga_connector/core/downloading/downloader.py	1	69.88%
src/ghga_connector/core/uploading/uploader.py	2	27.56%
src/ghga_connector/core/uploading/api_calls.py	2	58.96%

Totals
Change from base Build 9445402352:	-0.6%
Covered Lines:	1010
Relevant Lines:	1394

---

💛 - Coveralls

[Cito]

Looks good to me.