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).