signIn() does not store the roles property

[gr2m]

we currently selectively read out the username only, see https://github.com/hoodiehq/hoodie-account-client/blob/d3f86.

Ideally we should implement this more generic, there are also properties like createdAt, signedUpAt, updatedAt and maybe more in future. But I wouldn't mind to take a PR to fix the roles issue first and do a more generic solution later