Moved the Between squares table and Hyperbola function to chess/bitboard.

- Move sets of non-sliding pieces generated using bitboard shifts
- Change file grouping of various functions

Go files containing attack sets for chess pieces are now generated.

- Code generation with templates defined in .gotemplate files
- Declared utility functions used to generate code from templates

Rename symbols and make code more modular.

Magic tables are now populated when they are created.
Also useless fields have been removed from the structure.

N variables are the variables representing the quantity of something, like square.N

pkg/chess only contained the board representation so board is a better name.

Added some utility functions to make code more readable.