feat(stacked-diffs): Initial stacked diff support - adding metadata and stack refs

Description

Creating the initial command for stacked diffs. This doesn't do anything for right now, just adds the base command.

How has this been tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation
• Chore (Related to CI or Packaging to platforms)
• Test gap

Closes #7468 (closed)