Adjusting library definitions (follow-up to #30)

[IzzySoft]

This is a follow-up PR to #30 covering the remaining discussed adjustments.

Things still left to do:

• da;Mozilla;https://www.mozilla.org/: quite a bit broad
• da;Polidea;https://www.polidea.com/: same
• da;javax;: same again

Suggestion (as pointed out in #30): "Untagging" them now (i.e. emptying the "lib", removing the "pn"), and tagging them properly whenever encountered later?

Also left for a separate run: Introducing "df": "Development Framework" and retagging our candidates again.