v1.9.23-statediff-0.0.11

This is an internal release to enable us to work with the statediffing code (v0.0.11) using go modules. This release is rebased on top of master branch go-etheruem v1.9.23.

Updates:

Use Go 1.15
Fix API registration with new node interfaces
Statediffing service mode by which statediffs are generated and processed into IPLD objects and directly written to Postgres, this process can be configured to track the ongoing sync process and/or receive RPC requests to write diffs out at specific block heights