builder prune

Remove build cache

Name	Type	Default	Description
`-a`, `--all`	`bool`		Remove all unused build cache, not just dangling ones
`--filter`	`filter`		Provide filter values (e.g. `until=24h`)
`-f`, `--force`	`bool`		Do not prompt for confirmation
`--keep-storage`	`bytes`	`0`	Amount of disk space to keep for cache