add tilehierarchy structure

adding a structure that we can use to work with the configuration of where tiles should be and which levels should exist etc. this type encapsulates a `Tiles` object which can do most of the heavy lifting when it comes to getting a tile in a radius etc. I'll also want to use this in tandem with the `GraphTileReader` and loki to determine which tiles i'll want to read from cache etc.

the other thing this pr does is removes the stub valhalla binary src include and test junk since we have plenty of those on their own and no longer need the stubs.
Data members of structs, both static and non-static, are named like ordinary nonmember variables. They do not have the trailing underscores that data members in classes have.