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

packages/k8s/src/hooks/constants.ts

@@ -42,6 +42,7 @@ export function getSecretName(): string {
 export const MAX_POD_NAME_LENGTH = 63
 export const STEP_POD_NAME_SUFFIX_LENGTH = 8
 export const JOB_CONTAINER_NAME = 'job'
+export const JOB_CONTAINER_EXTENSION_NAME = '$job'
 
 export class RunnerInstanceLabel {
   private podName: string