`ipfs update`: add built-in command, sunset `ipfs-update`



https://github.com/ipfs/ipfs-update#readme   is deprecated, but some users may still depend on it:

- add `ipfs update` command to kubo
- release final `ipfs-update` that datects repo version >16 and just calls `ipfs update` instead
- archive https://github.com/ipfs/ipfs-update and update all docs `ipfs-update` → `ipfs update`