Make settings regexes optional

[djsiroky]

We pull office, project (name and number), and category fields from files using 3 settings fields:

• OfficeSiteExtractRegex
• ProjectExtractRegex
• PipeCategorizationRegex

If they are not present, we get a fatal error. I think we should both allow these to not be set (and either not set the field or include a default value) and to allow the user to set a static value for project/office, possibly with a separate options settings key.