Add Initial Codebase for Integrations CLI

[Swiddis]

Description

Per issue #1451, this PR implements the basic initial setup for the integrations CLI. From the help page:

Usage: integrations-cli.py [OPTIONS] COMMAND [ARGS]...

  Create and maintain Integrations for the OpenSearch Integrations Plugin.  

Options:
  --help  Show this message and exit.

Commands:
  check    Analyze the current Integration and report errors.
  create   Create a new Integration from a specified template.
  package  Package the current integration for use in OpenSearch.

It has some robustness to be added after the API is ready, particularly with regard to generating and validating sub-components such as saved objects. The current implementation only generates a configuration and references the local schema files.

The PR also creates a CI workflow that tests the new Python code.

TODO before converting from draft:

• Documentation
• More robust error handling
• General code cleanup

Issues Resolved

Part of progress on #1451. This issue can safely be archived and superseded by smaller-scope issues.
Conflicts with #1454.

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[YANG-DB]

Please add a README.md file at the root of the integration-cli package

[Swiddis]

Updated TODO list:

• General Code Clean-up
  • Work on reworking usage of returns (first experiment was sloppy)
  • Fix up error handling
  • Break commands into smaller units for testing
• Error handling in clear non-happy-path cases
• Fix the CI pipeline
• Add more testing
• Switch to Pytest for consistency with other OS CLI tools
• Convert to a proper Python package
• Actual dependency management and validation
  • Detect when components contain other components and add them
  • Validate if subcomponents are missing
• Improve catalog searching functionality
• Proper automatic integration uploading