Update issue templates

Author: rubenhoenle

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,25 @@
+---
+name: Feature request
+about: Suggest an idea for the STACKIT CLI
+title: ''
+labels: enhancement
+assignees: ''
+
+---
+
+## Problem description
+
+*Is your feature request related to a problem? If so, please give us a clear and concise description of what the problem is. 
+Example: I'm always frustrated when [...]*
+
+## Proposed solution
+
+*A clear and concise description of what you want to happen.*
+
+## Alternative solutions (optional)
+
+*A clear and concise description of any alternative solutions or features you've considered. (optional)*
+
+## Additional information
+
+*Feel free to add any additional information here.*