Add hash fragment as an optional method to supply config variables.

Add hash fragment as an optional method to supply config variables.

Any config variable like host, port, password, token may be
specified either in the query string (like now), or in the URL hash
fragment. In case a given variable is present in both, the value in the
fragment takes precedence. Supplying variables in the fragment avoids
leaking them to the web server hosting the noVNC viewer HTML.