Update key-requirements.md

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

 # Key Requirements 
 
-This is a short requirement specification
-
+This is a very short requirement specification
 
 ## Purpose of solution/product
 
-**What is a purpose of software? What it will solve? Who will benefit?**
-
+**What is a purpose of software?**
 
-## End User/Stakeholders
+>Short description
 
-* tbd
-* tbd
-* tbd
+**Who will benefit?**
 
+>Users and stakeholders
 
-## Primary Functionalitys
+** Main functionalities
 
 * tbd
 * tbd
 * tbd
 
-## Links
-
+**Performance / Security** 
 
 * tbd
 * tbd