Update cdk fork to latest version v0.10.0 and open a PR

[vnprc]

We're currently running on a dated fork of cdk from v0.7.2 with new ehash code. We don't want to be maintaining a fork.

1. Update the https://github.com/vnprc/cdk hashpool2 branch to the latest from the upstream repo. (Last time I did this it was easier to just make a new branch and overlay the changes rather than attempt to rebase).

2. Open a PR to cdk to add ehash functionality

[vnprc]

Migrated to vnprc/cdk hashpool3 branch which is on v0.11 cdk. The heavy lifting is done. Now working towards a draft PR to the cdk repo.

[vnprc]

The heavy lifting is done.

lol

A few days after I rebased onto the latest cdk commit thesimplekid merged the bolt12 refactor. When I tried to rebase again I concluded that it would be cleaner to just reimplement the ehash changes on top of cdk...yet again.

This is a work in progress on the hashpool4 branch of my cdk fork. It's a much better foundation to build on because the codebase has been arranged to support multiple payment methods. This work will directly inform the development of a new NUT spec.