Remove installation of OMERO on Mac OS

[pwalczysko]

Re: https://omero.readthedocs.io/en/stable/sysadmins/unix/server-install-homebrew.html

As noticed on https://forum.image.sc/t/omero-server-installation-on-macosx-icegridnode-not-found/115624 - this workflow is not in use and not tested anymore and should be removed.

cc @jburel @will-moore

[pwalczysko]

cc @sbesson @joshmoore @dominikl

[imagesc-bot]

This issue has been mentioned on Image.sc Forum. There might be relevant details there:

https://forum.image.sc/t/omero-server-installation-on-macosx-icegridnode-not-found/115624/2