Add Application Signals .NET runtime metrics config

[bjrara]

Description of changes:
This PR allows customers to configure dotnet runtime metrics collection at cluster level.

Dependent PR:
aws/amazon-cloudwatch-agent-operator#279

Test

helm install--namespace amazon-cloudwatch amazon-cloudwatch-operator ./ \
--create-namespace --set region=us-east-1 --set clusterName=k8s-demo \
--set-string manager.autoInstrumentationConfiguration.java.runtime_metrics.enabled=false \
--set-string manager.autoInstrumentationConfiguration.python.runtime_metrics.enabled=false \
--set-string manager.autoInstrumentationConfiguration.dotnet.runtime_metrics.enabled=false \

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