Some new functionality from the 18f fork

[cmc333333]

Corresponds to

• Allow notices without links to the FR eregs/regulations-core#8 - allowing the notice structure to not have a federal register url. The associated changes to the parser and -site haven't been PR'ed but this updates the database in preparation.
• Better logging eregs/regulations-core#12 - adds better default logging, including a specific check for the same label appearing multiple times (due to parse errors)
• Add a basic auth layer eregs/regulations-core#15 - adds configurable Basic Auth protection, should you need want the write interface public