Instead let the mobile OS take care of opening the URL
in the appropriate application. Without target _blank,
iOS 13.2.2 on Chrome will open about:blank and immediately
close the tab instead of opening the store.

* Adds an option to set email through iframe API init and to stats.

* Simplifies configuring email and displayName in stats.

Removes enableStatsID as not needed as when off we are sending as callstats id xmpp resource which is unique per call and id must be something that sticks between calls (callstatsUsername).

* Adds email and displayName in stats config for mobile.

* chore(deps): Updates lib-jitsi-meet to latest dd31f0a.

* Removes enableStatsID from config and whitelist.

It crashes on Android. Well, on the JSC version React Native uses on Android.

While we could use this fallback only on Android, we have decided to use it
on all mobile platforms for consistency.

iOS 10 crashes, so don't use it there, in any case.

Currently only 2 options are implemented, mainly aimed at helping troubleshoot
audio related problems:

- Disable native call integration (it disables CallKit / ConnectionService)
- Disable P2P

- Remove network-activity "feature"
    - It wasn't in use
    - It relied on internal React Native components, bound to break anytime
- Show an infinite loading indicator
- Style it just like the LoadConfigOverlay
    - Since it kinda represents the opposite, an "unload" then SDK is done

decodeURIComponent is not needed any more and after adding a validation such meeting name should not happen to be stored.

We are downloading code off the Internet and executing it on the user's device,
so run it sandboxed to avoid potential bad actors.

Since it's impossible to eval() safely in JS and React Native doesn't offer
something akin to Node's vm module, here we are rolling our own.

On Android it uses the Duktape JavaScript engine and on iOS the builtin
JavaScriptCore engine. The extra JS engine is *only* used for evaluating the
downloaded code and returning a JSON string which is then passed back to RN.

None of them work on mobile.

- use AbortController for setting the fetch timeout
- use async / await syntax for clarify
- set the default timeout to 5s (previously non-existent, aka 0)
- add ability to load but not evaluate a script

They never worked on mobile and pose an impediment for makinf config.js more
future proof. Specially if we want to move to a non-executable form of
configuration.

For now all keys are whitelisted.

- simplify initialization procedure
- set user display name as the Etherpad name\
- use SharedDocumentButton