DOCSP-28055 Adding PR Template shell (#246)

Author: ianf-mongodb

.github/pull_request_template.md

@@ -0,0 +1,23 @@
+## DESCRIPTION
+
+
+## STAGING
+
+
+## JIRA
+
+
+## BUILD LOG
+
+
+## Self-Review Checklist
+
+- [ ] Is this free of any warnings or errors in the RST?
+- [ ] Is this free of spelling errors?
+- [ ] Is this free of grammatical errors?
+- [ ] Is this free of staging / rendering issues?
+- [ ] Are all the links working?
+
+## External Review Requirements
+
+[What's expected of an external reviewer?](https://wiki.corp.mongodb.com/display/DE/Reviewing+Guidelines+for+the+MongoDB+Server+Documentation)