doc: add issue templates

.github/ISSUE_TEMPLATE/enhancement.md

@@ -0,0 +1,18 @@
+---
+name: Enhancement Request
+about: Suggest an idea for this project
+
+---
+
+
+**Is your feature request related to a problem?/Why is this needed**
+<!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] -->
+
+**Describe the solution you'd like in detail**
+<!-- A clear and concise description of what you want to happen. -->
+
+**Describe alternatives you've considered**
+<!-- A clear and concise description of any alternative solutions or features you've considered. -->
+
+**Additional context**
+<!-- Add any other context or screenshots about the feature request here. -->