Optimize block insertion and block input retrieval

Currently, using the stress-test CLI we are getting:

`miden-node-stress-test seed-store --data-directory ./data --num-accounts 100000
`
- For 100k accounts took ~3.5 mins: https://hackmd.io/w0x1h5q4QbSu5uBZtwv-IA
- For 1M accounts took ~48 mins: https://hackmd.io/_5OIqh9UQ625NyU4wgeo2A

Originally posted by @bobbinth in https://github.com/0xPolygonMiden/miden-node/issues/763#event-17018689947
> I think the target we should aim for is when the DB has 100M accounts, block insertion should be around 200ms, and GetNoteInputs should be around 50ms.