Provide list of installable userscripts to user; show links to userscript pages; auto /web_reload when necessary

Changes:

1) provide a list of known userscripts to user.
USERSCRIPT_REPOSITORY_URL in the commited version of hook.js is currently hardcoded to "beham.biz".
When the new app.js server script is deployed to phob.net, the URL should be changed as mentioned in the TODO.
The list of know userscripts is currently defined in public/qlhmUserscriptRepository.js.
Ideally we should use a URL/hoster where multiple people can modify the list (e.g. GitHub, ...)

2) when a userscript was deactivated, the "Close" button is replaced with "Restart" and executes /web_reload.

3) userscript names are now hyperlinks to the script pages on userscript.org

4) "Save" renamed to "Apply" in the Hook Manager