Add support for exporting an importing service dialogs

[branic]

These rake scripts and classes provide functionality for exporting/importing of the following ManageIQ object types:

- Service Dialogs

This PR uses the framework that was implemented for PRs #14126, #15256, #16717, and #16983 to export/import other ManageIQ object types.

These scripts are based on the CFME RH Consulting Scripts and are used by Red Hat consultants to enable storing customizations in Git and maintaining customizations between environments (e.g. dev/qa/prod) for an SDLC lifecycle.

Service Dialog export/import has been implemented using the same functionality that is used by the UI for performing the exports and imports. This PR also deprecates use of the dialogs rake task.

Links [Optional]

• Tracking Issue: Implement export/import functionality of Miq objects via command-line

Steps for Testing/QA [Optional]

Exporting

1. Create a directory for the exports

mkdir /tmp/service_dialogs

2. Export service dialogs

vmdb
bin/rake evm:export:service_dialogs -- --directory /tmp/service_dialogs

Importing

1. Import all service dialog yaml files in a directory

# vmdb
# bin/rake evm:import:service_dialogs -- --source /tmp/service_dialogs

2. or Import specific service_dialog yaml file

# vmdb
# bin/rake evm:import:service_dialogs -- --source /tmp/service_dialogs/Simple_Dialog.yaml

[miq-bot]

This pull request is not mergeable. Please rebase and repush.

[miq-bot]

Checked commit branic@6826237 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
6 files checked, 0 offenses detected
Everything looks fine. 👍

[eclarizio]

LGTM 👍