Todo: Add note field to !joinwatch

[FloatingMilkshake]

It would be helpful to be able to include a note when a user is joinwatched, so that there is context for the alert when they join or leave. Typically there is a considerable amount of time between when a user is joinwatched and when they join or leave next, so the context is most likely forgotten and requires digging through logs. Having a quick blurb or link to a modmail thread log in the joinwatch alert would resolve this.