Index unfinalized blocks

[stwiname]

Now that historical data is supported we can have the ability to index blocks that are unfinalized, and blocks that don't finalize can be rolled back so that we keep correct data.

A use case of this is that it reduces the delay between interactions with the chain and data from subquery

Todo:

• use flag --unfinalized to enable the feature
• once a project is upto the latest finalized block, start indexing unfinalized blocks.
• Roll back any indexing of unfinalized blocks that are dropped and unfinalized
• Add the ability to filter by finalized data, this would effectively result in the current behaviour.