Refactor gendynapi.py to make it more re-usable

[madebr]

In a later stage, we should probably turn it into a python module that can be imported.
This would be useful for generating tbds and ymls for llvm-ifs.

Description

Existing Issue(s)

[sezero]

What is the minimum python3 version required after this?
My python3.7 fails with the following:

Traceback (most recent call last):
  File "./gendynapi.py", line 62, in <module>
    @dataclasses.dataclass(frozen=True)
  File "./gendynapi.py", line 66, in SdlProcedure
    parameter: list[str]
TypeError: 'type' object is not subscriptable

[madebr]

What is the minimum python3 version required after this? My python3.7 fails with the following:

3.9: array subscript https://mypy.readthedocs.io/en/stable/cheat_sheet_py3.html#useful-built-in-types

(3.9 is the oldest version not in EOL)

[madebr]

If you really need 3.7 support,
you can add the following at the the top

from typing import List

and replace all list[...] typing annotations with List[...].
And similarly for tuple and dict.

[sezero]

OK, I'll build a 3.9 version. Thanks.