nmcli has a heuristic when setting the team-config to accepting both
a filename or the plain json text.
Add support for two schemes "file://" and "json://" to explicitly
determine whether to read from file or from json.
Also, no longer silently ignore an all-whitespace word. That is an
error (unless you have a file named " ").
Also, no longer replace newlines with space. Don't mangle the input
text at all.
c1a4c084b0