add remaining patches from common to allow switching over to source

This are just a few additional (optional) patches, that I've only used in the common repo.

To finally be able to deprecate it, I'll have to get them over here ;)

The dbus-patch is used to ensure proper dbus signalling / naming / pathes work in more restrictive environments (like flatpak or maybe even firejail). Shouldn't do anything on win/macOS, shouldn't hurt for the other linux-y releases.

unity-menubar.patch is from https://packages.ubuntu.com/bionic/firefox. Sometimes things break on major releases, so every now and then one has to wait for upstream changes, unfortunately.

mozilla-kde.patch is the patch from openSUSE to integrate better with kde.

Since that one and the unity-patch modify a few of the same things, there's also mozilla-kde_after_unity.patch, which is just the leftover stuff the kde-patch would do in addition to what's already covered by the unity-patch.