Implement yaml extensions overwriting the default pod/container spec (#75)

* Implement yaml extensions overwriting the default pod/container spec

* format files

* Extend specs for container job and include docker and k8s tests in k8s

* Create table tests for docker tests

* included warnings and extracted append logic as generic

* updated merge to allow for file read

* reverted back examples and k8s/tests

* reverted back docker tests

* Tests for extension prepare-job

* Fix lint and format and merge error

* Added basic test for container step

* revert hooklib since new definition for container options is received from a file

* revert docker options since create options are a string

* Fix revert

* Update package locks and deps

* included example of extension.yaml. Added side-car container that was missing

* Ignore spec modification for the service containers, change selector to

* fix lint error

* Add missing image override

* Add comment explaining merge object meta with job and pod

* fix test

examples/extension.yaml

@@ -0,0 +1,30 @@
+metadata:
+  annotations:
+    annotated-by: "extension"
+  labels:
+    labeled-by: "extension"
+spec:
+  securityContext:
+    runAsUser: 1000
+    runAsGroup: 3000
+  restartPolicy: Never
+  containers:
+  - name: $job # overwirtes job container
+    env:
+    - name: ENV1
+      value: "value1"
+    imagePullPolicy: Always
+    image: "busybox:1.28" # Ignored
+    command:
+    - sh
+    args:
+    - -c
+    - sleep 50
+  - name: side-car
+    image: "ubuntu:latest" # required
+    command:
+    - sh
+    args:
+    - -c
+    - sleep 60
+