Rebase of #1 onto real `v5` branch.
* Updates to the v5 schema, by linking the statediff plugin (as of this branch cerc-io/plugeth-statediff#15). This replaces the existing builder code.
* Adds basic CI workflows
* Updates Docker config and docs, cleans up some things
Co-authored-by: Thomas E Lackey <telackey@bozemanpass.com>
Reviewed-on: #2
Co-authored-by: Roy Crihfield <roy@manteia.ltd>
Co-committed-by: Roy Crihfield <roy@manteia.ltd>