feat: runner-type input for configurable runner selection

[pwn-0x309]

PR check-list

• Branch has a clean commit history
• Additional tests are included, if changing behaviors/core code that is testable.
• Proper Copyright + License headers added to applicable files (Generally, we stick to "The ZMK Contributors" for copyrights to help avoid churn when files get edited)
• Pre-commit used to check formatting of files, commit messages, etc.
• Includes any necessary documentation changes.

[urob]

What's the use case here? I fear that adding such config option might falsely promise portability across runners, which generally isn't guaranteed even among Linux runners (and definitely isn't for others).

(NB: I do see some merit in upgrading to Ubuntu-24.04, after testing compatibility, mainly for runner availability.)

[pwn-0x309]

hi @urob , I want to run ci jobs on my self-hosted runners.
We might adjust the default runner to be ubuntu-22 as your original config