Revise and "backport" driver fixes from 42ITy fork

[jimklimov]

There was a fair amount of both cross-pollination and independent evolution between "upstream" NUT project and 42ITy fork at https://github.com/42ity/nut/commits/FTY over the past years. Many PRs were developed in one and ported to another shortly, others were double-posted, but not all.

In particular, the fork pioneered many Eaton/MGE/PowerWare driver fixes (USB HID, SNMP, NetXML), some in logic, some in mapping data, not all of which landed into the upstream yet -- at least, some of those sources do differ "substantially" (there are also differences due to style and warnings clean-up in the "upstream" NUT, and some due to other features developed in 42ITy such as the DMF feature).

Ideally, those changes should be cherry-picked to retain the original authorship and time references, which in many cases would mean conflict resolution and constraining the change-sets to just what impacts the drivers AND what did not make way into the modern state of upstream NUT by some other path.

[jimklimov]

Largely (fully?) addressed by #1319 and can be seen as subset of #1316