Fixes #38335 - Add job_diff_mode to allow Ansible Check Mode in Job Templates

[bnerickson]

Overview of Changes

This PR adds a separate job_diff_mode variable to the AnsibleRunner class which ultimately sets the --diff flag in the ansible-runner command. This allows Ansible Diff Mode to be set for Jobs when the new ansible_diff_mode checkbox is selected in Ansible Job Templates (see PR theforeman/foreman_ansible#764).

Implementation Consideration

None

Testing Steps

1. Add the changes in Fixes #38335 - Adding Ansible Diff Mode to Ansible Job Templates foreman_ansible#764 to your test environment.
2. Add the changes in this PR to your test environment.
3. Clone the "Ansible Roles - Ansible Default" Job Template.
4. In the clone's "Ansible" tab, select the "Ansible Diff Mode Enabled" checkbox and save the Job Template.
5. In the user-defined Ansible Playbook for the test host, add a "copy" task that changes or deploys a text file with dummy content to the test host in the /tmp directory. For examples:

  - name: Deploy test file
    copy:
      src: "/etc/ansible/roles/somefile"
      dest: "/tmp/somefile"
      owner: root
      group: root
      mode: 0644

6. Schedule a Job for the test host and select the cloned Job Category and Job Template. Execute the job, and verify in the job's "template_invocation" page that the dummy contents of the file are displayed when the file is changed/deployed.

Checklists

• I am familiar with the contributing guidelines.
• I have added relevant tests for my changes.
• I have updated the documentation accordingly.

Additional Notes

This PR is dependent on:

• foreman_ansible: Fixes #38335 - Adding Ansible Diff Mode to Ansible Job Templates foreman_ansible#764

[bnerickson]

It looks like the changes here conflict somewhat with the proposed changes in #98. I don't mind waiting for that PR to be approved/merged first and then merging those changes into this PR when the time comes.

[ekohl]

I started a review of #98 and I think most comments also apply here.

[bnerickson]

Rebased after changes merged in #98

I also added a missing statement in test/fixtures/action_input.json for "diff_mode": "false",.

[bnerickson]

Hi @nofaralfasi , I see this PR is approved. Is there anything pending before this PR may be merged?