Shall we start asking new PRs to use SYSTEM instead of True

[Micket]

Going forward, we agreed that it's a good idea to start using SYSTEM instead of True for system level dependencies.

Discussed briefly on todays conf call, but I think it's best if we start by

1. Doing a big PR where we at least change most of the recent stuff to use this. Otherwise, it will be an never-ending stream of new contributions that copy old stuff and then get asked to change it. Very annoying and a time waste.

2. Have the CI check for this automatically.

[jfgrimm]

Doing a big PR where we at least change most of the recent stuff to use this. Otherwise, it will be an never-ending stream of new contributions that copy old stuff and then get asked to change it. Very annoying and a time waste.

done in PR #16386, and a few that were originally missed (or merged in the meantime) in #16384

Have the CI check for this automatically.

addressed in #16384

A PR to update the easybuild documentation was also merged in easybuilders/easybuild#827, and instances in the framework tests updated in easybuilders/easybuild-framework#4094

[Micket]

we do this now (edit: see #16384)