Chris/host key value store
This MR introduces the host registry. It allows for registering pubkey - value pairs on the host.
This is the first in a series of MRs and only introduces the registry + unit testing. The next one will hook it up to the host and add the RPC code.
Review and complete the checklist to ensure that the MR is complete before assigned to an approver.
- All new methods or updated methods have clear docstrings
- Testing added or updated for new methods
- Any new packages are added to Makefile and .gitlab-ci.yml
- API documentation updated for API updates
- Module README.md updated for changes to workflow
- Issue added to Sia-UI repo for new supporting features
- Changelog File Created