Completely refactor how regions are handled across everything

[Rathoz]

Regions are handled like shit right now, with patchwork here and there, partial support in other places etc etc.

Refactor with a clear (wiki-specific) hierarchy.

Could be:
Country (Germany) -> SubRegion (DACH) -> Region (EU) -> SuperRegion (EMEA)

or for more flexibility:

Country -> Parent -> Parent -> Parent -> (...)