Add QTH locator

[saturasvati]

Describe the idea (required)

QTH locator (also Maidenhead Locator System) are used in amateur radio for describe geographic coordinates. It would be very beauty if this app able to use this system.

Tell us about the expected behaviour (required)

It's should show QTH with other coordinate formats when some point selected and find position by it like any else coordinate format.

Tell us about alternatives you've considered (required)

Maybe it's not required for all users so it's could be made as external plugin. Maybe this plugin exist but I didn't find.

Context (optional)

No response