[8.1] Drop support for python 3.9 and 3.10?

[aldbr]

Do we still want to support python 3.9?

BEGINRELEASENOTES
ENDRELEASENOTES

[chrisburr]

I don't feel strongly either way but if we remove it we should also edit here:

DIRAC/setup.cfg

Lines 17 to 24 in d011057

	Programming Language :: Python :: 3.9
	Programming Language :: Python :: 3.10
	Programming Language :: Python :: 3.11
	Topic :: Scientific/Engineering
	Topic :: System :: Distributed Computing
	[options]
	python_requires = >=3.9

[fstagni]

We can remove from integration branch only.

[aldbr]

We can remove from integration branch only.

I changed the base branch: integration is now used.

I proposed this PR because I am getting used to the new typing syntax that we are using in diracx and I am starting to use it in DIRAC. And because there are a few differences between typing in py3.9 and py3.10-11 (e.g. Optional[str] vs str | None), it becomes "mentally difficult" to switch from one to the other.

Either developers just don't use the typing in DIRAC/use it with the py3.9 syntax, or we drop support for py3.9.

[fstagni]

I see nothing wrong with this. If there's a different opinion, leave it below, merging early next week.