Refactor Grammar Structure

The current structure of the grammar places all levels of TL to depend and be defined at the STPL branch of logic. However, it is more useful and readable to split the grammar into their respective TLs and import them to the superset grammars. E.g., STPL will import TQTL which will import TPTL which will import STL/MTL which will import LTL which will import FOL, etc.