Rename the team functionality enablement from 'teamdctl' to 'team'.
Force jansson lib requirement for team functionality: NetworkManager
requires the teamd daemon to manage team. As teamd depends upon jansson
lib, adding jansson requirement for teaming support in NetworkManager
seems reasonable.
Remove the jansson_validation flag, as the only generic json function in
nmcli (not related to team) was the one to check if a string was in json
format. Anyway, that function is used for team checks only. So, move
also json validation functions under the WITH_TEAM flag.