Split system.yml in two

[johndgiese]

The regulatory/data/system.yml file contains two types of information:

• Configuration values (e.g., repository and software_requirements_location.
• Global variables that are used in templates

These two types of information should be split into two separate files.

1. regulatory/_config.yml, which should contain configuration (this is analagous to the similarly named file in Jekyll)
2. regulatory/data/global.yml, which should contain global variables used in the default templates; these values should not have special semantics