Clear db after some time

[geleeroyale]

We need to be wary of not filling disk space completely.

The DB should have a way to automatically purge data - @mhmdksh implemented something like this for DeVouch

[aminlatifi]

@geleeroyale Do you mean we must apply modifications to the docker-compose or docker file?
Normally, the subsquid server won't store much data, just the state like a cursor pointing to the block height synced for each chain.