Renaming tier ban lists

We are renaming tier ban lists: BL is now UUBL, BL2 is now RUBL, BL3 is now NUBL, and BL4 is now PUBL. The new naming reflects that, for example, UUBL Pokemon are UU by usage but banned from the corresponding format (and thus only playable in OU, Ubers, and AG).

Hikari on Apr 24, 2018