pmos-ui-*: add initial patches supporting systemd installs

These patches that start supporting systemd for UI meta packages seem to be safe to pick from the systemd staging branch, and having them in master would simplify rebasing that branch. It would also get them additional testing on edge and reduce the number of patches we are carrying in the systemd branch.

I assigned this to the UI package maintainers, please have a look and help testing (with openrc) if you can. These patches have been tested somewhat against systemd, but the important thing here is that they don't introduce any new regressions on openrc/edge!

The following patches can be dropped from the master_staging_systemd branch once this is merged:

• f531627b - main/postmarketos-ui-plasma-desktop: set pkgver to 9999 to be higher than master branch
• e7d2fe70 - main/postmarketos-ui-plasma-mobile: set pkgver to 9999 to be higher than master branch
• 29c4ac50 - main/postmarketos-ui-plasma-{mobile,desktop}: start with systemd
• a8746ea7 - postmarketos-ui-phosh: systemd support
• d74f9010 - main/postmarketos-ui-sxmo-*: set pmb:systemd-never
• 290e02d8 - main/postmarketos-base-ui: support systemd
• 62326b4d - main/postmarketos-ui-gnome-mobile: set pmb:systemd
• e321c957 - main/postmarketos-base-ui-gnome: split openrc depends to -openrc subpackage