Unique permission to administer 403 to 404 settings

Problem/Motivation

The settings form for this module is currently protected by the "administer site configuration" permission.

Adding an unique permission just for administering the settings for this module instead of the blanket system permission to would allow for more flexibility when granting permissions to site administrators.

Proposed resolution

• Add new permission to module
• Update to grant existing admin users the new permission
• Extend tests to include the permission and the update step

Remaining tasks

• ✅ File an issue
• ✅ Addition/Change/Update/Fix
• ✅ Automated functional testing coverage
• ➖ Code review
• ➖ Credit contributors
• ➖ Release notes snippet
• ❌ Release

User interface changes

Users needing to change settings on module will need the "administer 403 to 404 settings" permission.

API changes

n/a

Data model changes

n/a