frontpage improvements

• For apps that require login, only show them to logged-in users.
• For logged-in users, show a "Configure" icon in the details for each service listed on the front page. This should link to the main app page.
• Suggestion to use larger icons.
• Front page configuration form: Select which services to display.
• Front page configuration form: Redirect to a specific service.
• Consider using much larger icons with text below the icon.
• Make each shortcut have a fixed height, so that there aren't any gaps.
• Show the info box right below the selected icon.
• If available, use Javascript to show the info box, so we don't have to reload the page.
• The Configure button doesn't conform to Bootstrap guidelines.
• Find better icons to distinguish apps (especially if we are emphasizing the icon over the text). Consider other icons sets besides glyphicons. Another suggestion is to use actual icons or logos of the included applications.
• Move welcome text to bottom of page, and center.
• Use scalable images.