feat: ISO build action (blue-build#133)

* feat: base iso release workflow
* does not produce a functional ISO yet
needs boot_menu

* chore(dev): start iso workflow on iso push

* fix: rename release-iso to release-please

* refactor: use github-cli to create release

* fix: remove job dependencies

* chore: basic boot menu

* fix: add permission to create release

* fix: delegate tag for auto-iso releases,..
delete old version when rerunning

* fix: multiline string for multine cmds

* fix: specify gh repo in old release delete

* fix: only create release if doesn't exist

* fix: boot menu double user field

* fix: clobber iso

* chore: neutral defaults for boot menu

* feat: run iso when iso-related changes pushed

* docs: README section for ISO