Android Studio won't build the app otherwise. Since the gradle plugin 3.0 beta7,
the minimum supported build tools version is 26.0.2, so set it to that. Also
bump compileSdkVersion to 26 since they need to match (in the major number, that
is).

The target API is still 25. Android Oreo (26) brought some changes in overlay
permissions which I haven't figured out yet.

The preceding commit "fix(auth.native): trigger conference left on
cancel" did not correctly clean the redux state up on CONFERENCE_LEFT.

Triggering the 'conference left' action when the wait for owner dialog
is dismissed will let the Call Kit implementation end the call, after
a recoverable conference failed event was emitted.

Also fixes conference state reduction when 'conference left' is emitted
by room lock or auth features where the conference has not been joined
yet.

ref(strophe): Remove and cleanup all strophe related code.

Everything strophe related is now handled in lib-jitsi-meet project.

e09949be9f introduced the dark theme globally, but
it only applies to web, so move the logic to App.web.js

Fixes few changes around changing devices

fix(config): Auto hide connection indicators by default

feat(dark-theme): Applies dark theme on inline-dialogs, tooltips, flags and more

Fix device selection popup

feat(desktop-picker): Add spinner and disable button if sources aren't initialized.

fix(desktop_sharing): if remote control is disabled

The feature authentication affords recovery from CONFERENCE_FAILED
caused by AUTHENTICATION_REQUIRED. (Like the feature room-lock afforded
recovery from CONFERENCE_FAILED caused by PASSWORD_REQUIRED.)

Recently/as part of the work on taking into account the user defined by
JWT, the local participant (on mobile) started telling the remote
participants that he/she had the display name "me". Obviously, that's
incorrect. Do not store the default display name in redux. While it may
be argues that redux is the place for all states, base/participants and
the name property of Participant is not meant to be that display name
because that is being sent to remote participants, the default name
needs to be internationalized, etc. So it's better to not store the
default display name at this time at all because it's not used by mobile
anyway and Web already deals with remote participants who don't share
their display names.

fix(ContactListPanel): default display name

chore(deps): remove unused.

Adds application name to the initJitsiConference options.

A few occurrences of coding style/formatting which I noticed while
reviewing 'feat(eslint): Enable for non react files'. These are
definitely not all occurrences I could've noticed during the review
but... we're talking about files outside react/ anyway.

Will override email, display name and avatar URL with the values
provided in 'context.user' structure of the JWT token.

Settings will no longer be used to retrieve local display name,
email and avatar URL. Now those values will be obtained from
the /features/base/participants Redux state.

fix(jwt/middleware): use const for default name

fix: wrong default display name on web

ref(base/participants): remove getDisplayName functions

ref(jwt): do not accept unknown user fields

* doc: document disableH264 option

* [RN] Override disableH264 config option

We never want it disabled on mobile.