There should be a way to insert blocks during runtime

[fl0rek]

Currently, there isn't mechanism to notify the behaviour that new blocks have been inserted into the blockstore manually (rather than coming from bitswap network). While new incoming requests for inserted CID will be processed properly, if there's a peer that requested that CID before it's inserted, they won't be sent this block on insertion.

idea: have blockstore be accessable through the behaviour, so that it can be notified of new CIDs and react to them.