Create state trie extractor

[mkrump]

From AFDudley:

The details of this need to be fleshed out a bit. But the general idea is we should create a tool for moving state trie data around. It should:

1. extract state trie data from a geth leveldb
   a. as JSON blobs
   b. as IPLD (maybe CBOR) blobs
   c. as some other efficient format.
2. inject state trie data into a geth leveldb
3. inject state trie data into IPFS (in support of Feature - expose state and chaindata via ipfs-http-api openethereum/parity-ethereum#4172)
4. inject state trie data into our postgres DB (if we do 3 I think we can skip this.)

[AFDudley]

@rmulhol this can be closed, right?

[rmulhol]

Subtasks 1.b and 3 are accomplished by this PR. The other tasks remain to be done, if we still want to do them.

[rmulhol]

Closing as we've broken this out into work on a Geth patch + syncAndPublish being overseen by @i-norden