add missing dependencies, style fixes, fix small bugs

This brings the easyconfigs repo up to speed for the v1.6.0 release.

A lot of dependency issues come forward when (re)testing builds on our systems that got an OS update and package cleanup effort.

Several easyconfigs required to resolve dependencies were stolen from the (yet) unmerged PR #330.

Unit tests pass, so all dependencies can be resolved, no conflicts are introduced.