Add contributing guidelines, issue templates, and PR template

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,22 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: "[FEATURE]"
+labels: ''
+assignees: ''
+
+---
+
+- [ ] I have reviewed this project's [contribution guidelines](https://github.com/SystemRDL/PeakRDL-regblock/blob/main/CONTRIBUTING.md)
+
+**Describe the problem/limitation you think should be addressed**
+A clear and concise description of what the problem is.
+
+**Describe the solution you'd like**
+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 about the feature request here.