If user types in https://nine.testrun.org/new manually
in the browser, at least Firefox and Brave suggest
to open the app after following the redirect.
* create a wwwdev.sh entry point for developing the web part
* rename script
* fix README
* add a note
* don't depend on deltachat python package
* avoid bailing out on jinja2 errors, and provide file-url for instant clickability
* in webdev mode make page auto-refresh every 3 seconds
