Create endeavour-college-of-natural-health

New dependent institutional style for the Endeavour College of Natural Health - http://www.endeavour.edu.au/ based on the University of South Australia style.
Update and rename endeavour-college-of-natural-health to endeavour-college-of-natural-health.csl

Renaming file to add csl extension and changing locale to en-GB.
Merge pull request #585 from Luboszot/patch-4

Create endeavour-college-of-natural-health