Revise driver man pages to include all known options (and their data types) #2422

Absence of documentation uncovered during work on #2294 (note also subsequent issues about proposed change of some option names and data types).

Some values seem to have been reserved in original development but are not implemented (check if they are commented-away; maybe use block comments /* ... */ with * prefix in each internal line for grep findings to be better visible - maybe update gen-nutupsconf-aug.py.in accordingly to ignore such lines).

Work on this issue (to update docs) can benefit from research done for #2294 and codified in the UpsConfiguration class of nutconf codebase.

One helpful data extraction scriptlet (just search for !!! in the less viewer session):

:; ( cd scripts/augeas && python ./gen-nutupsconf-aug.py.in )

:; grep -E '[=|] "' scripts/augeas/nutupsconf.aug.in | awk '{print $NF}' | tr -d '"' \
  | while read O ; do echo "=== $O :" ; \
    grep -w '"'"$O"'"' ./include/nutconf.hpp ; \
    grep -A10 -w "$O" ./docs/man/*.txt || echo '!!! UNDOCUMENTED !!!' ; \
    echo "-----"; grep -A10 -w '"'"$O"'"' ./drivers/*.{c,h} || echo '!!! NOT USED IN CODE !!!' ; \
    echo "-----"; echo "" ; done | less

NOTE: I'm sure there were other logged issues for man page revision but could not find them now. Maybe github ate some - there are certainly some issue numbers referenced from others and from code/commit comments that can not open now.