fix: allow certain keychain operations without a password

[achingbrain]

Listing, removing, renaming etc keys do not require a password so
the user should not be required to provide one.

This means we don't have to prompt the user to create a password
when they aren't going to do any operations that require a password.

[jacobheun]

I've update this to not require a password. I'll create an issue for supporting a password rotate feature. We should be able to set new passwords on they keychain. This will give us the ability to start without one and then "rotate" to one later.

[vasco-santos]

@achingbrain is this enough for js-ipfs to use libp2p's keychain without a password?

I believe that this needs to be changed: https://github.com/libp2p/js-libp2p/blob/master/src/index.js#L85

[jacobheun]

I believe that this needs to be changed: https://github.com/libp2p/js-libp2p/blob/master/src/index.js#L85

Good catch, I rebased with master and added a test for libp2p creation without a keychain pass.

[vasco-santos]

LGTM! 🚢

[jacobheun]

FYI I verified it fixes js-ipfs, ipfs/js-ipfs#3212. I'm working on bubbling it up there.

[achingbrain]

Thanks for pulling this across the line!