tools: add option to print full RMLVO elements to rmlvo-to-keymap Since the most common use-case is to provide only some elements of RMLVO, this makes it possible to show what is actually being used in the background based on the built-in defaults. Print this in a format that's mostly JSON-compatible or at least easy to parse, just in case. Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>