Introduce ResourceSets to make loading of resource files more flexible

added In Progress Theodolite Kotlin labels

This MR is still WIP, but for some early feedback, are you happy with this declaration of ResourceSets? @she The files field is optional, if it is not set, all available (yaml) files will be loaded.

appResourceSets:
    - FileSystemResourceSet:
        path: ./config
        files:
          - "uc1-kstreams-deployment.yaml"
          - "aggregation-service.yaml"
          - "jmx-configmap.yaml"
          - "uc1-service-monitor.yaml"
loadGenResourceSets:
    - ConfigMapResourceSet:
        configmap: "test-configmap"
        files:
          - uc1-load-generator-service.yaml
          - uc1-load-generator-deployment.yaml