Add Support for `following` a player

[MacMeDan]

The objectiveC example project had this idea that you could follow a TSUser this enables you to jump to another channel if they switch to another.

This Story would be to add this to the swift version of the project and then remove the ObjectiveC version.

Acceptance Criteria

• When selecting a User options are presented including a option to Follow that User.
  1. When the User switches channels your User also switches to the new channel

[MacMeDan]

@JanC would you mind adding the appropriate labels to this. This would be a task anyone could pick up.