Merge branch 'add-initial-architectural-diagram' into 'master'

Add initial architectural diagram

See merge request !2

.gitignore

+.idea/
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README.md

 # Documentation
 
+## Conceptual Diagram
+
+```mermaid
+flowchart LR  
+ A[Client]-- HTTPS -->B[API Gateway]
+  subgraph Trust Services API 
+   B-- HTTP -->C[Policy Engine] 
+   B-- HTTP -->D[Information Hub] 
+   B-- HTTP -->E[Signatures] 
+   B-- HTTP -->F[Cache]
+   B-- HTTP -->G[DID Resolver]
+  end
+```
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