Support all Monero wallet proofs

[kayabaNerve]

These include:

• SpendProofV1
• OutProofV2
• InProofV2
• ReserveProofV2

as detailed in https://web.getmonero.org/library/Zero-to-Monero-2-0-0.pdf.

This is distinct from #205 in that #205 is meant to be basic and functional, not compatible. This issue is for compatibility.

This would have a legitimate benefit to the library by being able to verify statements from wallet2. Supporting proving is less important, though still beneficial for the same reasons as wallet2 having all of these proofs (auditability and so on).

[kayabaNerve]

77be18a laid the ground work for OutProof by moving the r generation to a seeded RNG when a seed is specified. Wallets will be able to generate/save a seed if they want to be able to generate such proofs. prepare_payments can then be used to get all of the data necessary to make an actual proof.

[kayabaNerve]

Not planned, yet monero-wallet-util would be the lib for these.