Add a login prompt at first startup

[mxmvncnt]

Could be done via an API key or via master password. Pretty sure it would need to use the Keyring for safe storage of the login details. Would likely need an API key from the web vault as it is what the bw utility asks for on login.

Then we could save either the login details as well as the API key in the Keyring OR save the session id in the keyring and instead of using the server, use the cmd utility, but that would expose the session ID to other processes in the system, and by extension the entire vault contents