add step in iso workflow to remove unused software

[BobyMCbobs]

free up space as some builds require having as much space as possible

[noelmiller]

This is likely going to get overwritten with #7

I would wait until #7 is merged.

[JasonN3]

This wouldn't work in the workflow. The entire job runs inside of a container. The cleanup script would need to run on the container host. There are some ways to work around that, but it's either ugly in the workflow or bad security practice. So far, there has been enough space to build the ISOs since the container only needs to be downloaded once unlike when the containers are being built, which is a completely separate process.
The only reason it works in the current version of the workflow is because the entire workflow was ripped out and replaced with a docker run command. That is being changed back in the PR Noel mentioned.

[BobyMCbobs]

Thank you for taking a look.
I've just given it a go at
ii/image@9186922
and the build ISO job ran successfully
https://github.com/ii/image/actions/runs/7967193605/job/21749605247#step:4:648

I'm unsure how images like Bazzite would build without it given it's size, so I think it's important however it's implementation. Let me know if I can help!

[JasonN3]

I just tested building bazzite (https://github.com/ublue-os/isogenerator/actions/runs/7974763018). It did end up failing from lack of space. I added in some lines to my PR (ea1a7c9) to create some extra space using pretty much the same commands but adjusted to handle not running on the actual host. It will require the container to have the host mounted at /host, which is not good security, but the VM gets recreated for each run, so not a big deal if something happens to the host. I also left it as optional to have that mounted since most of the builds won't need it.

[BobyMCbobs]

closing since kinda covered in #7