Feature Request: Support mpd server with password

[milki]

mpd supports authenticating clients with a plaintext password:

https://www.musicpd.org/doc/html/user.html#permissions-and-passwords
https://www.musicpd.org/doc/html/protocol.html#connection-settings

When a password is set, the default permissions of an non-authenticated client is empty.

[danbee]

@milki This is definitely planned. I'm going to add it to the 0.18 milestone