Commit
4832352d02
replaced the plasma5 session startup
script with its upstream version from the
`pkgs.libsForQt5.plasma5.plasma-workspace` package.
In the course of doing so, the old session startup script
wasn't removed, but got moved into the display manager
startup shell commands option `displayManager.setupCommands`.
This now causes those commands to be executed
whenever the configured display manager starts.
The old startup script performed some basic
initializations in the user's home directory.
With the new arrangement, the old startup script is run with
HOME=/, leading to a lot of clutter in the root filesystem
(entries like `/.config` or `/.gitrc-2.0`).
The commit at hand simply removes the
old session startup script completely,
and with it a lot of now unused code from the plasma5 module.
5e635986ca