This can be done in 3 ways:
none: don't hide anything
all: hide all disabled elements (you can't re-enable in this state)
default: hide those elements whose parents are disabled
This had been left out for too long and makes it awkward for novices
to setup the networks. The config is possibly not as nice as before where
it was presented as a tree. But this can be improved later.
The API code has also been updated to use the htsmsg auto conversion of
strings to map/list where required. Basic approach is check for list/map
first and if that fails fallback to string (if that's whats appropriate
for a mixed type field).
