setup.py: Fix editable install with setuptools >= 64

The way editable installs are handled by setuptools has changed since release >= 64 and the custom develop command in setup.py is no longer called. As a consequence, the tree-sitter parser code generation was no longer executed when performing an editable install and runtime error was raised when executing the swh-search backend.

So use proper way to handle editable install with latest setuptools and ensure backward compatibility with older versions.

I checked the debian package builds were still passing after these changes, all good !