LinuxServer Changes:
Rebase to Alpine 3.19.
tvheadend Changes:
Fix echo target for superuser file in Debian postinst
aba5e60792177d6a2a867445559f4806973b3258 was causing the username
and password to get printed to the console instead of being put in
the correct file. Also, use the modern $() syntax instead of ``
and quote all variable assignments.