Add Tag registry for root tags key in OpenAPI 3

Currently needed is a system to collect and manage API tags from Grape API subclasses and integrate them into the OpenAPI 3.0 documentation generator.

Requirements:

• Create a tag registry system to collect all defined tags from API::Base subclasses
• Maintain a centralized registry of unique tags
• Integrate collected tags into the OpenAPI document's info section
• Ensure proper inheritance and collection of tags from all API endpoints

Technical Considerations:

• Duplicate tags should be handled appropriately
• The registry should be accessible during the OpenAPI document generation
• Tags should follow OpenAPI 3.0 specification format

A similar development method to #572529 (closed) would probably be appropriate.