[terra-overlay] Deprecate terra-overlay

[mjhenkes]

Feature Request

Description

terra-application provides an overlay and a loading overlay. Those components are recommended over usage of this component.

Update the terra-overlay package to indicate that it is deprecated.
Update terra-overlay documentation to indicate that it will be deprecated in the future using the deprecation notice.
Create a deprecation guide to direct people on how to migrate to terra-applications overlay.

Audit: #2970

Additional Context / Screenshots

@ Mentions

[stale]

This issue has been automatically marked as inactive because it has not had recent activity. It will be closed in seven days if no further activity occurs. Thank you for your contributions.