Enable systemd for uwsgi

[gdamjan]

Building with withSystemd=true makes the image twice as big, so currently I build images without systemd support.

Once the nixpkgs merges a solution to have a smaller systemd package, either by introducing a systemd.lib sub-package, or a minimal systemd option, change the github action to build withSystemd=true (the default option).

ps.
one of the pulls for minimal systemd is NixOS/nixpkgs#98998

pps.
Supplying withSystemd=true, changes the uwsgi build to include the systemd, or journal logging output plugin, which creates a bit nicer logs when running

[gdamjan]

building uwsgi against the systemdMinimal pkg makes the image from 30MB to 40MB - which is acceptable I guess. it's still not as small as if libsystemd.so would've been a package.

[flokli]

The nicer fix for this might be NixOS/nixpkgs#99382.