* feat(display-name): convert to React

- Create a new React Component for displaying and updating display
  names on small videos
- The updating of the Component is defined in the parent class
  SmallVideo, which children will get access to through prototype
  copying
- Create a new actionType and middleware so name changes that occur
  in DisplayName can be propogated to outside redux
- Update the local video's DisplayName when a conference is joined
  or else the component may keep an undefined user id

* squash: query for the container, not the el owned by react

When the prosody setting has muc_allowners, everyone joins as a
moderator. In this case, the local user will not be set as a
moderator in the redux store as the USER_ROLE_CHANGE event will
trigger with the local user id before the redux store has set
the actual local user id--something that happens on
CONFERENCE_JOINED. The fix is to explicitly signal the local user
role has changed to the redux store, which follows the
implementation of pre-existing web logic.

They better represent if a participant has video available or not. There are
cases when even a participant in the last N set would not have video because it
disconnected momentarily, for example.

Replaces changeAvatarID, changeAvatarURL and changeEmail with
participantUpdated action.
participantUpdated can be fired for local user without id. This
fixes the problem with updating the local user before the user
join the conference which results in fix for failing to execute
commands for avatarID, avatarURL and email right after the iframe
api creates the iframe with Jitsi Meet.

As an intermediate step on the path to merging jitsi-meet and
jitsi-meet-react, import the whole source code of jitsi-meet-react as it
stands at
2f23d98424
i.e. the lastest master at the time of this import. No modifications are
applied to the imported source code in order to preserve a complete
snapshot of it in the repository of jitsi-meet and, thus, facilitate
comparison later on. Consequently, the source code of jitsi-meet and/or
jitsi-meet-react may not work. For example, jitsi-meet's jshint may be
unable to parse jitsi-meet-react's source code.