Draft: Move the gitaly binary to allow for zero-downtime

What does this MR do?

Allows the previous gitaly to keep running until we hup it by using a copy of the binaries

TODO

• handle the configfile
• cleanup old dirs after hup
• also do something like this for the 'old' gitaly in the package preinst in order for the upgrade to 14.0 to go smoothly.

Related issues

Part of gitaly#3647 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• Pipeline is green on dev.gitlab.org if the change is touching anything besides documentation or internal cookbooks
• trigger-package has a green pipeline running against latest commit

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for the GitLab Chart opened