This didn't work with e2e calls and just ended up with everyone who
went to the URL creating their own room because it didn't add the
alias to any of them.
This has it show a very simple 404-esque screen instead. If the call
already exists, it will show it as before, so existing URLs will
continue to work.
by fixing the cause rather than the symptom: this upgrades the code to use the new, recommended JSX transform mode of React 17+, which no longer requires you to import React manually just to write JSX.
This is an Element project (in the vector-im repo) so the Copyright
should be for New Vector: it was incorrectly attributed to the
foundation for some files (and some files were missing headers).
