It modifies the applied connection using the Reapply API.

It makes sense to modify the applied connection from the device object.

Useful with connect, disconnect, delete, monitor, show and reapply.

Parsing a single device name from the command line is generally
useful. Remove the open coded versions in reapply, connect & status.

It will look nicer when we have get_device().

It's a semaphore, not a boolean.

For "nmcli d modify" we'll need to do the completion from async
handlers. This seems to be the most reasonable place to ignore the
errors.

Some functions that take device lists use plural form in name.