Theme editor style and theme config changes to support core component forms.

[muskgupta]

Description

This change covers adding style and theme configs for core components to support theme editor for core component based forms.

Related Issue

This is a new feature where theme editor is being supported for core component forms. Epic link : https://jira.corp.adobe.com/browse/FORMS-14719

Motivation and Context

Enables style and theme configs for styling references.

How Has This Been Tested?

Tested this change on local host by creating test server.

Screenshots (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] I have signed the Adobe Open Source CLA.
• [ ] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes and the overall coverage did not decrease.
• [ ] All unit tests pass on CircleCi.
• [ ] I ran all tests locally and they pass.