Fix nasa#210, Add Checklist to Feature Request Template

.github/ISSUE_TEMPLATE/feature_request.md

@@ -7,6 +7,12 @@ assignees: ''
 
 ---
 
+**Checklist (Please check before submitting)**
+
+* [ ] I reviewed the [Contributing Guide](https://github.com/nasa/cFS/blob/main/CONTRIBUTING.md).
+* [ ] I reviewed the [cFS README.md file](https://github.com/nasa/cFS/blob/main/README.md) to see if the feature is in the major future work.
+* [ ] I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.
+
 **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 [...]