Merge pull request #145 from NHSDigital/PPHA-416-infrastructure-architecture-diagram

feat: Add Infrastructure Architecture Diagram

Author: Themitchell

docs/diagrams/infrastructure/README.md

@@ -0,0 +1,7 @@
+# Solution Infrastructure
+
+<picture>
+  <source media="(prefers-color-scheme: light)" srcset="diagram-light.png?raw=true">
+  <source media="(prefers-color-scheme: dark)" srcset="diagram-dark.png?raw=true">
+  <img alt="Solution Diagram" src="diagram-light.png?raw=true">
+</picture>