Updates to Help Widget and Sidebar Pane

1. Make the Help Widget an optional `floating` or `titlePane` widget.

2. Change `toggleSideBar` function to `togglePane` making it more generic to accommodate additional Content Panes in the future (example is attribute list located below the map).

3. Allow the application to start with the sidebar closed (collapsed).
Why is this function being replaced? The sidebar needs to be store when not visible or errors occur with the toc and zooming in and out.