* Adds initial documentation for sipgw jibri.

Also explains enabling the people search service and the request/response that are made around sipgw jibri service.

* Fixes add people dialog to invite users and rooms.

No invitation is sent when there is nobody to invite.

* Reuse some recording strings, by using arguments.

* Make sure web also dispatches CONFERENCE_WILL_JOIN.

* Introduces new feature videosipgw.

* Fixes lint errors.

* Renames methods to use people, chatRooms and videoRooms.

* Updates to latest lib-jitsi-meet (dc3397b18b).

ESLint 4.8.0 discovers a lot of error related to formatting. While I
tried to fix as many of them as possible, a portion of them actually go
against our coding style. In such a case, I've disabled the indent rule
which effectively leaves it as it was before ESLint 4.8.0.

Additionally, remove jshint because it's becoming a nuisance with its
lack of understanding of ES2015+.

Prepare for React 16.

* feat(AddPeopleDialog): invite rooms

Distinguish between 'user' and 'videosipgw' search result items and
invite them with using different method.

* squash: fix typo in AddPeopleDialog.web.js

* Fix(AddPeopleDialog): Fixes error state and close dialog

* (to-squash) Addresses comments