- reinstall needs to know toolchain(s) as well.

Only 'install' needs to know about --ALL, etc.

(probably introduced by myself when breaking long lines in last MR)

- didn't pay attention to content
- didn't intend to change content or behaviour
- didn't execute tests

(We need some CI to catch at least the trivial mistakes like the one from the
last commit.)

as the function supports one or more arguments.

See discussion at
https://gitlab.gwdg.de/mpsd-cs/mpsd-software-environments/-/issues/1#note_799664

(fix https://gitlab.gwdg.de/mpsd-cs/mpsd-software-environments/-/issues/2)

(with ChatGPT)