Simplify parsing of HW requirements and add missing ones

[happz]

It turned out some requirements were left out and nothing was parsing them. The "maximal" unit test was incorrect and did not report this.

The patch

• adds parsing for missing requirement groups (gpu, device),
• several individual requirements were also missing,
• simplifies parsing of groups of constraints, providing helpers to avoid repetition,
• and fixes the test guarding this.

Pull Request Checklist

• [x] implement the feature
• [x] extend the test coverage