Various Scheme Updates

[rgchris]

• Initiate endpoints for Log and Clipboard schemes
• Rearrange the Storage scheme to facilitate more 'map'-like behaviour
• Initiate endpoints for the two Storage objects
• Document the Storage and File schemes

The endpoints for Log and Clipboard permit usage without URL notation (see: https://forum.rebol.info/t/non-network-related-schemes-and-urls/1506/25)