switch from elpy to lsp-mode in python

This required installing the following packages from bookworm:

elpa-lsp-mode python3-pylsp python3-pylsp-black  python3-pylsp-flake8 python3-pylsp-mypy python3-pylsp-isort

Otherwise lsp-mode looks for pyls, and that is not in Debian. And
pylsp is not in bullseye either.