feat: add tests for submodel methods #155

Job	Run time
AAS Discovery - Build and Start Docker Image	2m 6s
AAS Registry Kafka Mem - Build and Start Docker Image	2m 36s
AAS Environment - Build and Start Docker Image	2m 29s
AAS Registry Kafka MongoDB - Build and Start Docker Image	2m 38s
AAS Registry Log Mem - Build and Start Docker Image	2m 10s
AAS Registry Log MongoDB - Build and Start Docker Image	2m 23s
AAS Repository - Build and Start Docker Image	2m 9s
AASX File Server - Build and Start Docker Image	2m 13s
Concept Description Repository - Build and Start Docker Image	2m 13s
Submodel Registry Kafka Mem - Build and Start Docker Image	2m 32s
Submodel Registry Log Mem - Build and Start Docker Image	2m 12s
Submodel Registry Kafka MongoDB - Build and Start Docker Image	2m 55s
Submodel Registry Log MongoDB - Build and Start Docker Image	3m 0s
Submodel Repository - Build and Start Docker Image	2m 12s
Submodel Service - Build and Start Docker Image	2m 7s
	35m 55s

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