Renamed _QA_Protocols.md to 15_QA_Protocols.md and added this file to _toc.yml (#365)

* Rename _QA_Protocols.md to 15_QA_Protocols.md

* Update _toc.yml to add new file

Author: speco29

DISCOVER/_QA_Protocols.md renamed to DISCOVER/15_QA_Protocols.md

@@ -19,4 +19,5 @@ chapters:
 - file: 13_inclusive-checklist
   title: Inclusivity Checklist
 - file: 14_how_to_contribute
+- file: 15_OA_Protocols.md
 - file: _tags/tagsindex