BIT-0018: Distributed subnet ownership

Summary

The current Bittensor subnet ownership model creates significant limitations by registering ownership to a single on-chain entity. It offers no native mechanism to distribute ownership rights or rewards, hindering collaborative governance and investor participation. This PR introduces Distributed Subnet Ownership, a protocol-level solution that allows both economic and governance rights to be fractionalized into on-chain shares. This enables multiple stakeholders to co-own and manage a subne...