[GOKZ-Global] Add Warning message for starting runs on "unfiltered" courses

[walliski]

It would be nice to get a warning message (similar as when map is not global) when starting a run on a map that does not have a filter. For example when running a vnl_ map on kzt, or running a Bonus course that does not allow times for a certain mode.

Example message when starting timer: "Warning: The KZT mode is not allowed on course Bonus 1. Global times will not save."

As additional bonuses when making the plugin "filter aware", would be a command to list available filters for all courses on the map, and to prevent the plugin from trying to send times to the Global API in case the filter doesn't match.

Related Issues:

• #285
• #316