keyring.alt backend split

[buhman]

In jaraco/keyring@1e422ed, the the previously-default FileBackend is no longer present in keyring. It might be nice if hubble documentation mentioned this, because simply installing keyring will not result in a usable hubble-keyring.

[buhman]

I use SecretStorage now (depends on a working gnome-keyring), but I'm not sure what others use; maybe we should add a "show default backend" command to hubble-keyring to make it easy to poll hubble users for what's actually happening, so that we can document a suggested least-common-denominator backend.

[thrawn01]

New key ring back-end in 2.0

[buhman]

Not done yet ;p