CID tracking database

[gammazero]

Track CIDs used within kubo for determining how they are used (pinning, mfs, dag root, etc.) and for performing efficient GC.

[guillaumemichel]

CID tracking database would implement reference counting for CIDs, massively improving garbage collection and notifying routing systems of which CIDs should be provided/stop being provided.

This requires significant effort since it requires modifications to MFS, pinner, blockstore and probably other components as well.

Related to:

• More intelligent blockstore garbage collection #3092
• No GC #4382
• [META] Garbage Collection Enhancement/Rework #7752
• https://hackmd.io/bgU7ti6_THK5gAGcrAhoEw
• IPFS Garbage Collection v2 protocol/web3-dev-team#8