Merge debian/latest into main to make the package truly a native package

Everything in the structure of this package looks like it is a native package (debian/* contents, the artifacts that lack a separate debian.tar.xz tarball), but the upstream and Debian versions life on different branches making the package in effect non-native. Merge the Debian packaging on the main branch, and continue doing packaging and upstream development on the 'main' branch to rectify the situation and have the package correctly be a native package.

Add salsa-ci.yml for additional QA.

This MR and !3 are mutually exclusive depending on if the maintainer decides to keep package native or non-native.