Merge duplicate M.U.T.O. tag

BUR #11577 has been approved by @evazion.

create alias muto_(monster) -> m.u.t.o.

These duplicate tag are for the same monster from Godzilla franchise.

deprecating and then further nuking after a tag has already been aliased is entirely pointless. Pick one, not three.

Talulah said:

deprecating and then further nuking after a tag has already been aliased is entirely pointless. Pick one, not three.

Done.

The bulk update request #11577 (forum #218228) has been approved by @evazion.