* ref(contact-list): remove invite functionality
Removing becuase there is already a toolbar button dedicated
to opening the invite dialog. Now the contact list focuses
on showing current participants.
* squash: remove unused strings and styling
* squash: add plural to panel title
Instead of going through the Avatar object, call the getAvatarURL
directly so that the code flows consistently use the participant
representation within redux.
- Remove references to the model ContactList.
- Replace ContactListView with an empty element for attaching
the React Component ContactListPanel, which has the same
features as the old ContactListView.
- Create new selector for getting non-fake participants for
ContactListPanel's props.
- Create a ParticipantCounter component to place in the contact
list button. Previously ContactListView updated that but now
it's a react component hooked into the participant state.
- Remove pub/sub that was used only by ContactListView.