Add program types and methods, type hinting

[kpp]

• Add types: Authorization, Boolean, Credits, Execution, Fee, Field, Group, Identifier, I{8-128}, Literal, Locator, MicroCredits, Process, Program, ProgramID, ProvingKey, Query, Response, Scalar, Trace, Transaction, Transition, U{8-128}, Value, VerifyingKey;
• Add a basic test to create a public_transfer transaction with a calculated fee;
• Add type hinting.

Tests should be run with maturin develop --release, otherwise the proof generation takes too much time.

[kpp]

Note: Do not create a pypi release, there is a new pr coming which will automate it: https://github.com/kpp/python-sdk/pull/1