Update key-requirements.md

docs/20-Requirement-management/key-requirements.md

@@ -14,17 +14,28 @@ This is a very short version of requirement specification
 * tbd
 * tbd
 
+## Primary needs for customer
 
-## Primary Functionalitys
+* as a <role> I would like to <act>, because <rationale>
+
+## Primary Functionalitys/Features
 
 * tbd
 * tbd
 * tbd
 
+## Non functional Requirements
+
+* Security?
+* Performance?
+* Availabiltiy?
+* Usability?
+
+
 ## Links
 
 
-* tbd
-* tbd
-* tbd
+* [Customer]()
+* [Some Background]()
+* [Other Issues]()