gdk update / bootstrap improvements

What does this Merge Request do?

This MR is a follow-up to !1608 (merged) and extracts the asdf plugin/tools update logic out from Makefile and moves into support/asdf-update. We also update asdf and add/update asdf plugins that are defined in https://gitlab.com/gitlab-org/gitlab-development-kit/-/blob/master/.tool-versions only.

Closes: #1092 (closed)

Merge Request checklist

• Tests added for new functionality. If not, please raise Issue to follow-up.
• This change is backward compatible. If not, please include steps to communicate to our users.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.