Adds latest still supported ubuntu lts templates

[madalinignisca]

I wanted to add a few more ubuntu lts templates that I use often on local work I do and thought it would be useful for others to have them available.

[AkihiroSuda]

Should we now mv ubuntu.yaml ubuntu-24.04.yaml; ln -s ubuntu-24.04.yaml ubuntu.yaml for consistency?

[madalinignisca]

Would be ok

[AkihiroSuda]

It is hard to keep every image up-to-date, so we may need to have an automation script before adding new templates

• Automation for updating templates #1347

[afbjorklund]

Ubuntu 16.04 and 18.04 are probably old enough to hide them from the general public (even if supported)

Having 20.04 and 22.04 should be old enough I think? And then we don't have to re-live all old bugs, like:

• Old versions of fuse have read-only config file #2387

Should probably delete centos-7.yaml (after tomorrow) as well, even if it is from 2014 rather than 2018...

[madalinignisca]

Sorry, but my intention with this PR is only to introduce common ubuntu templates, not change anything not having a relation with them.

I agree automation to ensure latest releases would be great, but even in my case, an update after deployment is not such a pain, as usually even in public cloud environments, full upgrade is part of my cloud-init setup (even public cloud ain't having latest and greatest releases).

For next step, I'm willing when I get some time off for some automation for some of the templates that concern me, being Debian and Ubuntu, as I don't use any other distributions for server work.

[AkihiroSuda]

We now have an updater for Ubuntu (https://github.com/lima-vm/lima/blob/master/hack/update-template-ubuntu.sh), so this PR can be revisited again after rebasing.

[AkihiroSuda]

This should be probably removed due to EOL

[AkihiroSuda]

Opened an alternative PR:

• templates: add ubuntu-20.04, ubuntu-22.04 #2795