Replace pkg_resources

[jburel]

This PRs allows to install and run OMERO.web with Python 3.12
The following errors happened when attempting to run OMERO.web on Ubuntu 24.04:

File "/opt/omero/web/venv3/lib/python3.12/site-packages/omero/cli.py", line 1677, in loadpath
#11 23.38     exec(f.read(), loc)
#11 23.38   File "<string>", line 24, in <module>

and

39.68   File "/opt/omero/web/venv3/lib/python3.12/site-packages/pipeline/__init__.py", line 1, in <module>
39.68     from pkg_resources import DistributionNotFound, get_distribution
39.68 ModuleNotFoundError: No module named 'pkg_resources'

See ome/omeroweb-install#98