Dynamic filters

[robdmoore]

Support the ability to add filters dynamically based on the information retrieved in blocks (potentially re-running those filters in the block that the new filter was discovered in?).

Need to figure out if indexer catchup mode can be supported by this or not - it would be tricky to do, but may be possible.

Requires #27

We will need to include a filter persistence mechanism similar to watermarking.

Idea: either allow entire filters to be dynamically added, or allow a static set of filters to reference a "dynamic filter value", which resolves to an named array value that can be looked up.

Question: do we re-run the modified filter for the current block or does it take effect from the next block (simpler).

[PhearZero]

Was looking into this today a bit, this would be the main blocker for governance transactions.

• On Payment Transaction With Governance Note
  • Lookup Account Balance and compare against Commitment
  • Update AccountState
• On Dynamic Account Watch List
  • Lookup AccountState and Balance
  • Compare state to Balance
  • Update AccountState

I couldn't think of any other way than Follower Mode + Dynamic Filters in order to solve the problem. We can easily orchestrate the state in the node and get the current balances to validate the payment transaction commitment. Not sure about how the filter will react to it

[robdmoore]

I've got it mostly implemented in #45 - just needed final polish, but been distracted since then...