Murisi/masp test vectors

[murisi]

Describe your changes

Implemented the random generation of MASP test vectors and slightly altered MASP-related transaction sections to facilitate the printing of shielded amounts with correct denominations. More specifically, the changes are as follows:

• Used proptest to generate random shielding, shielded, and deshielding MASP transactions
• Implemented a MASP TxProver to aid constructing these transactions with the following properties:
  • It is faster than LocalTxProver since it does not generate any zero-knowledge proofs
  • It is more correct than MockTxProver since it generates binding signatures that the hardware wallet will check
• Improved the formatting of MASP transactions by using the new denomination information
• Modified the AssetType derivation to be parameterized by a token's token::Denomination
  • Needed for hardware wallets to safely display and sign shielded denominated amounts
  • Modified the MaspTxBuilder supplied to hardware wallets to include token::Denomination in the preimages

Indicate on which release or other PRs this topic is based on

#2371

Checklist before merging to draft

• I have added a changelog
• Git history is in acceptable state

[batconjurer]

Overall looks fine. I'm somehow hung up on the name PreAssetType, but really that's minor.