fix: fix and refactor AoT css

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

If action is null (observed on some old devices) we'll get an exception.
Reversing the check fixes it since Actions.XXX is statically defined.

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

See: https://github.com/jitsi/jitsi-meet/issues/4720

This adds an option to disable video autoplay that will be used mostly with maleus (our selenium-based load testing tool for testing the new bridge). Disabling video rendering lowers the resource utilisation of the selenium nodes.

It's available on both Xcode 10 and 11.