[P] Move diagrams into a dedicated directory

diagrams/use-case.puml

@@ -0,0 +1,23 @@
+@startuml
+rectangle IoT-Systems {
+  usecase "Collect telemetry (accelerometer + GPS)" as uc1
+  usecase "Send telemetry" as uc2
+  usecase "Process telemetry" as uc3
+  usecase "Determine road condition (pothole / bump /\nnormal)" as uc4
+  usecase "View road defect marks" as uc5
+  usecase "View route on map" as uc6
+}
+
+rectangle "The user is the card operator" as uc10
+rectangle "Sensor Agent\n(Device/STM32/Emulator)" as uc11
+
+uc11 - uc1
+uc11 - uc2
+
+uc10 - uc5
+uc10 - uc6
+
+uc2 -.|> uc3 : <<include>>
+uc3 -.|> uc4 : <<include>>
+
+@enduml