Statediffing service at v1.9.11

This is an internal release to enable us to work with the new state-diffing service code using go modules. For this release have rebased on top of go-etheruem v1.9.11.

Other changes since the last release:

• Emit actual leaf nodes instead of value nodes
• Emit node paths for all nodes and node paths + leaf keys for leaf nodes
• Diff on the leaf nodes instead of on value nodes