Add manual_confirmation on stage json

What does this MR do and why?

1. Add manual_confirmation in Jobs keyword
2. Return confirmation_message in stage.json
3. Return confirmation_message in StatusAction graphql.

Connected to: #450715 (closed)

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Before	After

How to set up and validate locally

1. Add manual_confirmation on job that we want to have manual confirmation

   1. You can use this example YAML

      stages:
        - build
        - second_stage
      
      build-job:
        stage: build
        script:
          - echo "11111..."
          - echo "Compile complete."
        manual_confirmation: This is Manualllll
      
      build_artifact:
        stage: build
        script:
          - echo "11111..."
          - echo "Compile complete."
        manual_confirmation: This is Manualllll

2. Push to repository
3. confirmation_message key should present in the stage.json
4. confirmation_message should present in StatusAction graphql