add issue templates

.gitlab/issue_templates/Change Request.md

+## Summary
+<!-- Outline the issue being faced, and why this needs to change !-->
+
+## Area of the system
+<!-- This might only be one part, but may involve multiple sections !-->
+
+## How does this currently work?
+<!-- the current process, and any associated business rules !-->
+
+## What is the desired way of working?
+<!-- after the change, what should the process be, and what should the business rules be !-->
+
+## Priority/Severity
+<!-- Delete as appropriate. The priority and severity assigned may be different to this !-->
+- [ ] High (This will bring a huge increase in performance/productivity/usability, or is a legislative requirement)
+- [ ] Medium (This will bring a good increase in performance/productivity/usability)
+- [ ] Low (anything else e.g., trivial, minor improvements)