add command to (slowly) prune lotus chain datastore

[whyrusleeping]

No description provided.

[whyrusleeping]

Decent example usage:

./lotus-shed state-prune --delete-up-to=5000000 --use-bloom-set

Note: the gc part at the end takes a loooong time and doesnt really seem to clear everything up. You can run:

./lotus-shed state-prune --only-ds-gc

to just run badger gc in a loop for 20 times.

[travisperson]

This is a global flag: https://github.com/filecoin-project/lotus/blob/master/cmd/lotus-shed/main.go#L46-L51

[magik6k]

lint sad

[s0nik42]

Hello ! Is this safe to use compared to the previous proposition of @ribasushi to delete the chain content folder and import the pruned version of the chain ?

Thank you !

Julien