Add black and isort formatting CI stage

Run formatting check using both black and isort --profile black. The isort will check that the imports are properly sorted according to PEP8.

Use a new Python script under the tools/format.py. The script can either be run in the format mode which will format all Python files and check which will check the formatting.

Use the Debian 12 image to make the black version consistent. Otherwise when black updates the formatting style will change.