Ensure testnet repo is ready for release and link into provenance main readme.md

[iramiller]

Summary

The main readme for the provenance project should reference information on how to join the current testnet and view its current status using the explorer. The details of how to connect to the testnet and its configuration should be documented in the separate testnet repository.

Proposal

• Update the testnet repository with remaining requirements to open as a public repository
  • [x] License file attached
  • [x] Root Readme in place with links/info on current and upcoming testnets
  • [x] Code of conduct (can copy from provenance repo
  • [x] Contributing guidelines (cut/paste what makes sense from provenance version)
  • [x] Pull request template in place with info on how to contribute correctly to the genesis files for testnets
• Ensure testnet repo is set to public once prep steps are complete
• For any larger missing documentation pieces or scripts, open an issue in testnet for tracking
• Add a section to the provenance repo that describes the testnet and directs people to the other repo for details
• Add links to the publicly accessible blockchain explorer instance for the testnet

[iramiller]

This is related to provenance-io/provenance#96

[iramiller]

This issue is largely house keeping and ensuring that the testnet repo is complete and ready to publish publicly. Some of these steps may need to be broken out into other issues in the Explorer projects (@crussell-figure will know more about that)