Region restricted (public / private) Giveaways

Since region restricted public giveaways are still public giveaways, we should be able to see them but not join, a red button like the one that says that you already own the game but saying "not for your region" would be great. The same should apply to Private giveaways that you have the link.

This way we can have more information on those giveaways that are crucial for some sgtools functions: check if winner really activated a GA on multiple copies giveaways, allow parsing of private region restricted GA to create filtered region restricted GA, etc.