This fixed the problem of applications like Calibre and OBS
crashing and complaining about the platform even though the
platform plugin was correctly found. Any ways anything still
depending on X needs to die.
We were setting these in fish shell setup during login. Move them
here so that they can be correctly inherited by systemd services.
Without this, the tmux session service does not get the environment
variables which do not get set by the time tmux session service starts.
https://www.freedesktop.org/software/systemd/man/environment.d.html
