Update to v5 schema

[roysc]

Basic refactor and CI update

[i-norden]

Hmm something is wrong in CI, log messages aren't particularly helpful. Looks like docker is having issues with the "migrations" image (ipld-eth-db). The v5.0.0-alpha version should work but we should change it to v5.0.1-alpha anyways.

[roysc]

Shall we also tag this as v5.0.1-alpha?

[i-norden]

@roysc we should tag this v5.0.0-alpha.

The convention we use for any repo that depends on ipld-eth-db is that its major version should correspond to the major version of the version of ipld-eth-db that it works with. The minor and patch versions float independently for each repo, so that you can make changes to those codebases that don't require changing the version of ipld-eth-db being used. Likewise, changes to ipld-eth-db which don't break backwards compatibility with dependent repos should bump the minor or patch versions and any schema change that breaks backwards compatibility should be a major version change.