Prototypes booleans and relational operators. As part of this I removed `FFI/Data/Bool.agda`, because it was getting in the way - we already use `Agda.Builtin.Bool` instead for other cases.
Adds support for binary operations on numbers.
Adds number support to the prototype. Binary operators are next.
Introduces a test runner with test cases. Also significantly overhauls the GHA configuration.