drive_access_ft and drive_access_points_ft clarification

[lmz]

Right now the Description for lot_id is "Stop ID"; I think these should say Lot ID and further it would be handy if we said they're distinct from stop ids (e.g. they could be "lot1234").

They are also mentioned in transfers_ft's description, where we call them "park and ride/kiss and ride node". I think it would be more clear if we also called it a lot_id there too.