selinux: remove script and use docker :z notation to accomplish the same effect

[boxerab]

Hello!
This commit simplifies the handling of SELinux. Instead of a shell script, I have just modified
the docker compose template to add :z notation to volumes that need to be sandboxed for SELinux.
I have tested this on my Fedora system with a fresh clone and it all works - no extra script needed.

Cheers,
Aaron

[manisandro]

Judging by the comment here [1]

Use extreme caution with these options. Bind-mounting a system directory such as /home or /usr with the Z option renders your host machine inoperable and you may need to relabel the host machine files by hand.

I don't think it is a good idea to add this to the default docker-compose template. Rather, I'd just add a note in the README, pointing out also the risks.

[1] https://docs.docker.com/engine/storage/bind-mounts/#configure-the-selinux-label

[boxerab]

Judging by the comment here [1]

Use extreme caution with these options. Bind-mounting a system directory such as /home or /usr with the Z option renders your host machine inoperable and you may need to relabel the host machine files by hand.

I don't think it is a good idea to add this to the default docker-compose template. Rather, I'd just add a note in the README, pointing out also the risks.

[1] https://docs.docker.com/engine/storage/bind-mounts/#configure-the-selinux-label

Thanks, I wasn't aware of these warnings. However, I am using the lower case :z option in the PR, so there should not be any issues with the host machine. How would you feel about my creating a second docker-compose template for SELinux, and I can add a note in the README ? The only issue is that two templates must be maintained.