Feature Request: Do not use paths under $HOME as the default storage path #128
Description
As shadow currently creates multiple sub dir in $HOME, for example ~/.ethash and ~/.ethashproof, it increases the maintenance complexity. Users using docker and shadow will have to mount multiple volumes or mount $HOME as a volume which not only contains shadow data but also files like ~/.bash_history etc in the docker container. I don't think that's ideal.
For non-docker users, it is possible that they can run multiple shadow instances on a single VM. The default storage path will cause conflicts in that scenario.
My idea is that we can use the current working directory as the default storage path for shadow, which means if we launch shadow without additional options, it stores ethash and ethashproof in ./ethash and ./ethashproof.
It would be great as well if there's an option, such as --data-path or --storage-path that allows users changing the path specifically.