Provide digital signed Discover JNLP

If you're currently starting Discover you'll get 2 securtiy messages warning that the JNLP is not digitally signed. Would be great to have a signed JNLP to get rid of those 2 warnings.

If the dynamic content (session key and current report if started from the toolbar) cause issues, provide a static JNLP as a first step to have a "bookmark" on the desktop to start Discover without warnings.