refactor(mpz-ot): Normalize OT and ideal functionalities

[sinui0]

This PR normalizes our OT interfaces as well as completely reimplements our ideal functionality abstraction.

Nothing here touches the security critical logic of any of the OT implementations. This is purely a clean up and testing utilities.

Changes

• Ideal functionalities logic is now consolidated into mpz-ot-core instead of leaking into mpz-ot.
• Added an abstraction which makes it easier to implement ideal 2-party functionalities in mpz-common
• Every oblivious transfer call now has a TransferId
• Outputs for each OT functionality is now strongly typed.

[sinui0]

What is the benefit of adding an extra encapsulation layer for the OT return types in the traits?

It just provides stronger typing and a way to document what each field is. It's better to have the types defined in mpz-ot-core and the traits inmpz-ot work with them