Transition and full handover of the congested testnet to the SPO community

[nrutledge]

• [ ] The congested testnet is maintained by multiple SPOs, or MLabs has otherwise exhausted all reasonable options for gaining traction among community members and establishing full decentralization. Successful adoption of a network relies on third parties and adoption rate directly cannot be used to access pass or failure.
• [ ] The public has been informed that the testnet is no longer being maintained by MLabs and has been moved towards being fully decentralized.