Introduce ResourceSets to make loading of resource files more flexible

This MR introduces so called ResourceSets that allow loading Kubernetes manifests either via ConfigMap or from the file system.

Closes #240 (closed)

docs/patchers.md

+## Patchers
+
+* **ReplicaPatcher**: Allows to modify the number of Replicas for a kubernetes deployment.
+  * **type**: "ReplicaPatcher"
+  * **resource**: "uc1-kstreams-deployment.yaml"
+
+* **NumSensorsLoadGeneratorReplicaPatcher**: Allows to scale the nummer of load generators. Scales arcording to the following formular: (value + 15_000 - 1) / 15_000
+  * **type**: "NumSensorsLoadGeneratorReplicaPatcher"
+  * **resource**: "uc1-load-generator-deployment.yaml"
+
+* **NumNestedGroupsLoadGeneratorReplicaPatcher**: Allows to scale the nummer of load generators. Scales arcording to the following formular: (4^(value) + 15_000 -1) /15_000
+  * **type**: "NumNestedGroupsLoadGeneratorReplicaPatcher"
+  * **resource**: "uc1-load-generator-deployment.yaml"
+
+* **ReplicaPatcher**: Allows to modify the number of Replicas for a kubernetes deployment.
+  * **type**: "ReplicaPatcher"
+  * **resource**: "uc1-kstreams-deployment.yaml"
+
+* **EnvVarPatcher**: Allows to modify the value of an environment variable for a container in a kubernetes deployment. 
+  * **type**: "EnvVarPatcher"
+  * **resource**: "uc1-load-generator-deployment.yaml"
+  * **properties**:
+    * container: "workload-generator"
+    * variableName: "NUM_SENSORS"
+
+* **NodeSelectorPatcher**: Changes the node selection field in kubernetes resources.
+  * **type**: "NodeSelectorPatcher"
+  * **resource**: "uc1-load-generator-deployment.yaml"
+  * **properties**:
+    * variableName: "env"
+  * **value**: "prod"
+
+* **ResourceLimitPatcher**: Changes the resource limit for a kubernetes resource.
+  * **resource**: "uc1-kstreams-deployment.yaml"
+  * **properties**:
+    * container: "uc-application"
+    * variableName: "cpu" or "memory"
+  * **value**:"1000m" or "2Gi"
+  
+* **SchedulerNamePatcher**: Changes the sheduler for kubernetes resources.
+  * **type**: "SchedulerNamePatcher"
+  * **resource**: "uc1-kstreams-deployment.yaml"
+  * **value**: "random-scheduler"
+
+* **ImagePatcher**: Changes the image of a kubernetes resource. Currently not fully implemented.
+  * **type**: "ImagePatcher"
+  * **resource**: "uc1-kstreams-deployment.yaml"
+  * **properties**:
+    * container: "uc-application"
+  * **value**: "dockerhubrepo/imagename"