Split language detectors to be web/native dependent. Take care of strings that contain html.

Adds translate function with default namespaces and options.

The error raised by JitsiMeetJS.init() is already in the state of
features/base/lib-jitsi-meet so it's not a good design to store the same
error in the state of features/unsupported-browser.

`host` contains the hostname:port portion, whereas `hostname` is just the
hostname, not including the port.

When rendering using a for loop each child whould have a key prop.

This solves the issue of view clipping on Android, plus it seems to be the RN
convention unless the views are very large and memory hungry.

Fixes an issue where immersive mode would be enabled when coming back from the
background on the welcome screen.

Re-fixes c57e713, which was not correct.

It doesn't work properly and gives a very bad user experience. Disble it until
all underlying issues in react-native-webrtc are ironed out.

On RN we don't use the global APP object, so don't save the store there unless
it's defined, which is the case in the current web version. Also, check for
undefined explicitly, since a "if (!APP)" check will throw a ReferenceError.

The mobile app remembers the domain which hosted the last conference. If
the user specified a full URL first and specified a room name only the
second time, it was not obvious that the second conference would be
hosted on the domain of the first conference.

Looks like Android gets confused as to what surface to blit when we hide or
show toolbars. Setting a border on the container, seems to force the entire
area to blit properly.

Other attempted approaches, with no success:
- zIndex of -100
- width and height of 0
- opacity of 0 and setting 'disabled' on touch containers

This patch applies the workaround in the welcome page and conference containers.