The ability to play local-listening files without internet access

[mr-ransel]

Is your feature request related to a problem? Please describe.
If I'm out, away from my phone/internet access for my watch, but I already previously downloaded books for local listening, I should be able to play that file locally without having to login (without syncing or other features obviously)

Describe the solution you'd like
At app load, it would be great to have the option list any books that are already downloaded for local listening from any servers, then to select them for playback at the last-synced-timestamp

Describe alternatives you've considered
Require an Internet connection or Bluetooth connection to my phone to start playback initially, but this is a general inconvenience, since I only expose my ABS on my local network so I could only start playback/login from home.