Roadmap to v1

[tomMoulard]

Here's a list of targets in not particular order:

• [x] supportedBackend needs to be updated (fixed by #67)
• [x] Context.Context store support (#43)
• [ ] Change errors messages / types
• [ ] Clean unused errors
• [ ] Break down store configurations
• [ ] Review .golanci.yml issues
• [ ] Decide what to do with github.com/kvtools/valkeyrie/store/mock (use Mocktail?)
• [ ] merge or close the current PRs?