Refactor participants box

Split the `participants-view` into two separate compnents:
- `participants-box`: is passed the participants law and performs a request to `/api/citizen/lookup` to get the populated participants. Then `ParticipantsBox#load`s them into `.participants-container`
- `participant-view`: is passed a populated participant and renders the participant bubble using [tip](https://github.com/component/tip) when `switchOn` is called.