-auto-pin-rm option for ipfs name publish

[JayBrown]

Regarding the comments here: ipfs-inactive/faq#16 (comment)

Would be great to have an option to auto-remove pinned files from local storage, if they're not part of a directory anymore that has been content-edited & republished under the same ipns hash. (Obviously, this would also extend to publications under keys different from "self".)

Such an option might however need a bit of intelligence, i.e. it would also have to be determined if an ipfs hash that's not part of a revised ipns publication anymore, is still published under a different ipns hash (check across all keys); if it's still part of another ipns publication, that should override any auto-pin-rm option, and the individual file should stay pinned to local storage.

[whyrusleeping]

This might be a nice feature to have. Though it might be more user friendly to look at integrating ipns and mfs. Things in mfs are 'best effort' pinned, meaning none of the blocks you have locally for a graph will be garbage collected, but it doesnt require having all of the blocks. (this is very useful when you want to work with very large datasets lazily).

Ipns entries could automatically get put somewhere inside of mfs (meaning they are pinned). Then when updating them, they overwrite the old entry, thus unpinning it as a side effect.

Just a thought, doesnt necessarily have to be the direction we take.