Initial PR template for O3DE (#9912)

* Initial PR template for O3DE

Signed-off-by: Pip Potter <[email protected]>

.github/pull_request_template.md

@@ -0,0 +1,9 @@
+## What does this PR do?
+
+_Please describe your PR. For a bug fix, what was the old behavior, what is the new behavior?_
+
+_Please add links to any issues, RFCs or other items that are relevant to this PR._
+
+## How was this PR tested?
+
+_Please describe any testing performed._