Drop use of qtpaths in startkde
Summary:
Qtpaths doesn't work on some distros (Ubuntu for example, where it's
shipped with dev tools) and it's quite a slow way to effectively just read
an environment variable.
This is a rework of d90c63ac8fe54567dcf5f634f2112c6ab2aa1027 that
also correctly includes system directories.
Test Plan:
Put shell script in ~/.config/plasma-workspace/env
put shell script /etc/xdg/plasma-workspace/env
Rebooted. Confirmed both were run
Checked earlier 'if' statement works manually in bash.
Reviewers: Plasma
Subscribers: apol, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D9478