Implement channel slice

[hugoponthieu]

Implement the channel slice
This slice is needed to store the state of the connection in channels. It will manage this state:

export interface ChannelsState {
	focusedChannel: ChannelEntity
	connected: boolean
}

The focused voice channel is set to an empty channel when the user is not connected and the boolean is set to false.
You guessed it when the user connect to a channel it store this channel in the store and the connected boolean is set to true

This slice will expose two methods:

setFocusedChannel(state, { payload })

unsetFocusedChannel(state)

Example