Create an interceptor that writes snapshot data to rocks db for faster snapshot generation

[toneillbroad]

Add an interceptor that writes record payloads to rocks db during vrs-python transformer process. Need to also add code to retrieve the data from rocks db when generating snapshots. Not sure if he last part is the same interceptor or just code.

We discussed adding some new keys to the payload for:

• the name of the rocks db (in case you want separate databases)
• the key to use for storage