docs: Add a feature request template

Signed-off-by: Rob Bradford <rbradford@meta.com>

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,36 @@
+---
+name: Feature request
+about: Request a feature or enhancement
+title: ''
+labels: ''
+assignees: ''
+type: Feature
+---
+
+**Elevator pitch**
+A clear and concise description of what the feature (or enhancement) is.
+
+**Motivation**
+Why is this feature important to you? What problem does it solve? Why should we
+carry this feature?
+
+**Prior art**
+Examples of similar features in this project or similar (e.g QEMU, Firecracker,
+Crosvm, etc)
+
+**API/CLI**
+Does this feature require any API or CLI changes?
+
+**Testing**
+Can it be tested? Any special CI requirements?
+
+**Interactions**
+How does this feature interact with existing features (e.g. hotplug, live
+migration, etc).
+
+**Implementation**
+Do you have an Implementation already? If so link to the branch.
+
+**Full feature description**
+Please ensure the structured section above is completed and then fill out this
+section with any additional details you want.