GitLab: Add "Default" Merge Request template

.gitlab/merge_request_templates/Default.md

@@ -0,0 +1,57 @@
+## What does this MR do?
+
+<!-- Is there a lot to say? Consider creating an issue. -->
+
+## Screenshots  <!-- Optional -->
+
+### Before
+
+![alt text](https://example.com/before.png)
+
+### After
+
+![alt text](https://example.com/after.png)
+
+## Notes
+
+* This MR
+  **does**  <!-- KEEP ONLY ONE -->
+  does not  <!-- OF THESE LINES -->
+  change more than 3 files / 100 lines of code.
+
+  <!-- If so, what’s the connection? Or, could you split it into multiple MRs? -->
+
+* This MR
+  **does**  <!-- KEEP ONLY ONE -->
+  does not  <!-- OF THESE LINES -->
+  introduce new methods.
+
+  <!-- If so, are they tested? -->
+
+* This MR
+  **does**  <!-- KEEP ONLY ONE -->
+  does not  <!-- OF THESE LINES -->
+  modify or remove existing methods.
+
+  <!-- If so, did you modify/remove their tests, as well? -->
+
+* This MR
+  **does**  <!-- KEEP ONLY ONE -->
+  does not  <!-- OF THESE LINES -->
+  add to, modify, or remove existing test cases.
+
+  <!-- If so, explain. -->
+
+### Other Considerations  <!-- Optional -->
+
+<!--
+Does your MR need one of the following labels?
+
+* Performance Impact
+  (Keep in mind that some instances process 2,000+ tickets per day.)
+
+* Follow-up Required
+  (e.g., Do we need to coordinate with the documentation/support teams?)
+
+If so, apply it and explain here.
+-->