Add display name for permission roles and use it in ListRoles

[rdimitrov]

Summary

The following PR:

• Extends the ListRoles response to include the role display name
• Adds a map of openfga roles to their display names
• Update the description for each role

Fixes #(related issue)

Change Type

Mark the type of change your PR introduces:

• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[coveralls]

coverage: 53.461% (+0.007%) from 53.454%
when pulling b50b39f on role-display-name
into b351409 on main.