Increase the stack size from 4 to 22

[marcesquerra]

Both, Moon and MonadLifter has 4 versions of it's interface (one for each stack size). That is clearly not scalable and hard to maintain.

(Note: By stack size I mean the number of monads that can be stacked one inside the other)

The idea would be to implement a small source code generator that generates the two files (with 22 versions of their respective interfaces). And then, integrate it with sbt (in the source code generation step)