Move patch to publish asc files out of the collabora folder

It is an upstream-able patch (it was already submitted upstream),
so there is no collabora specifics here.

debian/patches/series

 backend-publish-udebs-in-repo.patch
 publish-ddeb-files.patch
-collabora/publish-asc-files.patch
+publish-asc-files.patch
 database.yml-settings.patch
 gemfile-tweaks.patch
 drop-test-and-development-depends.patch