Store orchard nullifiers into the state

[oxarbitrage]

Motivation

We need to store nullifier data for orchard in the state. #1983

Solution

Add a new column to the database (and to the spec) to store the new data.

The code in this pull request has:

• Documentation Comments
• Spec updates
• Unit tests with actual nullifiers: commit Transaction V5 test vectors to an ephemeral state
  • see the existing unit tests that use ephemeral state
  • we want prop tests like this: https://github.com/ZcashFoundation/zebra/blob/main/zebra-state/src/service/non_finalized_state/tests/prop.rs
  • but using the finalized state:
    • https://github.com/ZcashFoundation/zebra/blob/main/zebra-state/src/service/finalized_state.rs#L37
    • https://github.com/ZcashFoundation/zebra/blob/main/zebra-state/src/service/finalized_state.rs#L176
  • and maybe the state service like this: https://github.com/ZcashFoundation/zebra/blob/main/zebra-state/src/service/tests.rs#L15
• Integration Tests for empty nullifier lists: Rebuild the cached state for the integration CI tests
• Integration Tests with actual nullifiers: Run Zebra after NU5 testnet activation

Review

@dconnolly can take a look. I followed the advise of using the sapling nullifiers as a guide.

[oxarbitrage]

this PR seems to also cover partially #1982

[dconnolly]

Looks good, two small changes I'd like to see 😎

[teor2345]

Let's split off the changes from #1982 into their own PR, so we don't accidentally forget any changes.

I also suggested a few updates to comments to make them more accurate.

[teor2345]

I just filled in the test plan for this change:

• Integration Tests (empty nullifier lists): Rebuild the cached state for the integration CI tests
• Integration Tests (actual nullifiers): NU5 testnet activation

We'll have to come up with a better plan for testing the stable release in NU6.
But for NU5 we can just test alphas after testnet activation.

[teor2345]

I just filled in the test plan for this change:

• Integration Tests (empty nullifier lists): Rebuild the cached state for the integration CI tests
• Integration Tests (actual nullifiers): NU5 testnet activation

We'll have to come up with a better plan for testing the stable release in NU6.
But for NU5 we can just test alphas after testnet activation.

We should also be able to write unit tests that take a NU5 test vector and commit it to an ephemeral state. So I've added those.

[teor2345]

I'd like to remove the "add anchor" and "remove anchor" comments, because we're not actually doing that yet. (This is an old problem with the comments, but we should fix it now.)

[teor2345]

I think your test vector might have found a bug in Zebra. Nice!

Let's change the tests to use random data (you'll need PR #2208), and do a few small cleanups.

[teor2345]

This is looking good.

I did a bunch of work in #2221 that should make implementing these proptests easier.

[teor2345]

Looks good, I'll just apply a comment fix then merge.

Old review