Dropping support for Python 3.8

[Avasam]

CPython 3.8 is EOL as of October 7 2024 (last week).
Anaconda is dropping support at the end of the month (I'll keep as draft until then)

Highlights represented by these changes:

• PEP 584, union operators added to dict;
• PEP 585, type hinting generics in standard collections;
• PEP 616, string methods to remove prefixes and suffixes.
• PEP 593, flexible function and variable annotations;

Testing in dev mode as per:

You should check for DeprecationWarning in your code
[...]
More generally, try to run your tests in the Python Development Mode which helps to prepare your code to make it compatible with the next Python version.

Also of interests, we now have unconditional access to the zoneinfo module: https://docs.python.org/3/whatsnew/3.9.html#zoneinfo, which may or may not be usable as part of win32/Lib/win32timezone.py.

[Avasam]

I've included adodbapi changes here as they have many overlap with #2094. If @vernondcole doesn't get to review this PR by the next release after the end of this month, then I'll split them up.