chore(docs): Added contribution templates, SECURITY policy

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,28 @@
+---
+name: Feature request
+about: Suggest an idea to improve ERPNext
+labels: feature-request
+---
+
+<!--
+Welcome to ERPNext issue tracker! Before creating an issue, please heed the following:
+
+1. This tracker should only be used to report bugs and request features / enhancements to ERPNext
+    - For questions and general support, checkout the manual https://erpnext.com/docs/user/manual/en or use https://discuss.erpnext.com
+    - For documentation issues, refer to https://github.com/frappe/erpnext_com
+2. Use the search function before creating a new issue. Duplicates will be closed and directed to
+   the original discussion.
+3. When making a feature request, make sure to be as verbose as possible. The better you convey your message, the     greater the drive to make it happen.
+-->
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**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 screenshots about the feature request here.