docs: FAQ by categories as proposed by @anarcat in #1802
docs: FAQ by categories as proposed by @anarcat in #1802

Usage & Limitations
Security
Common issues
Miscellaneous (only three items, two fork-related)

Note: This does not change any links to FAQ items.

RonnyPfannschmidt/borg,edgimar/borg,RonnyPfannschmidt/borg,edgewood/borg,edgimar/borg,RonnyPfannschmidt/borg,raxenak/borg,raxenak/borg,edgimar/borg,RonnyPfannschmidt/borg,edgimar/borg,edgewood/borg,edgewood/borg,raxenak/borg,raxenak/borg,edgewood/borg,RonnyPfannschmidt/borg