in-memory realtime sync

[kyscott18]

The "sync" portion of ponder handling extracting and ordering events is entirely in-memory, removing the need for database queries. Another property is that only finalized data is added to the sync-store. This is a combination of #1092 and #1103. Closes #1091.

This involves:

• storing child address information in memory
• filtering, formatting, and ordering events, (replacing getEvents())

Child address methodology

• separate unfinalizedChildAddresses and finalizedChildAddresses
• track factoryLogsPerBlock, so that unfinalizedChildAddresses can always be recomputed
• on reorg, evict reorged blocks from factoryLogsPerBlock and recompute unfinalizedChildAddresses
• on finalization, add child addresses from finalized blocks to finalizedChildAddresses, evict finalized blocks from factoryLogsPerBlock and recompute unfinalizedChildAddresses

TODO

• pass factory information to buildEvents
• handle back-pressure when a block becomes finalized before it has been indexed
• test (address casing + getChildAddress, + buildEvents)