refactor mongo schemas

[iquidus]

some refactoring of schemas could potentially improve performance.

for example, adding txn trace to the txn itself (even if duplicated).
adding txns in full to blocks (even if duplicated)

approach from a query perspective. minimize queries even if it requires duplicating data in mongo, storage is a cheap price to pay for faster responses/load times.

[iquidus]

The heavy lifting should be on write, once, by the crawler, not on read, everytime.