Implement tab-completion for uploaded media, and add bungee support

[Mindgamesnl]

Uploaded media tab completion

• automatically tab-complete media from your account, prefixed with files:
• the media cache will be updated in real-time if people are connected to the client, or is fully refreshed when the first player connects

Bungee

• Implement tab completion for players and media on Bungeecord

Proxy bypass command

• Users can now use /oas or /openaudiospigot to bypass the proxy for some commands, which will also enable tab-completion for playlists and aliasses