systemd: disable units by default, fix/update some presets

The change in !5207 (merged) doesn't seem to do anything, resulting in some weird stuff being enabled by default even though we did not specify a preset for it (e.g. see !5556 (merged))

Based on my interpretation of the systemd preset manpage, this file should be parsed last. It says that if a unit name has a preset that was already configured in some previously parsed preset file, then any matches after do not apply. This means that the disable * should not disable any previously enabled (in previous .preset files) units. When the unit name is omitted from the disable command, it seems to be a no-op.

Fixes !5207 (merged)

This also updates the base presets in pmos-base-systemd, fixing some that were incorrect and adding a preset for sshd