Use custom player class

[varma02]

Is your feature request related to a problem? Please describe.
I want to store my bot's queue and other music related info. I also want to modify the play command for spotify playback support.

Describe the solution you'd like
I want to be able to pass in a custom class when I use the Node.players.get() function.
Like this:

class CustomPlayer extends Player { 
// Code
}
const node = new Node({options})
node.players.get('guildId', CustomPlayer)

Describe alternatives you've considered
None

Additional context
None

[appellation]

If this were to be implemented, it should be implemented as an option on PlayerStore and provided as an option in the instantiation of the BaseNode. Unfortunately, the typings involved with that are complex and not something I can take on at this time. If you can make it work, feel free to open a PR.

Otherwise, I recommend tracking your application-specific fields on a separate struct.