feat!: refactor tool discovery into extensible parser registry pattern

[nallenscott]

Implement Parser Registry Pattern to enable support for multiple API specification formats beyond OpenAPI. This creates a clean, extensible architecture for future Postman Collections, GraphQL, and other formats.

Changes:

• Create parsers module with APISpecParser abstract base class
• Implement ParserRegistry for parser management and discovery
• Extract all OpenAPI logic into OpenAPIParser class
• Refactor OCPSchemaDiscovery to orchestration layer using registry
• Add comprehensive tests for parser components
• Update exports to include new parser classes

BREAKING CHANGE: Private methods moved from OCPSchemaDiscovery to OpenAPIParser class. Methods like _parse_openapi_spec(), _normalize_tool_name(), _filter_tools_by_resources(), and others are no longer accessible on OCPSchemaDiscovery. Code using these private methods should use the OpenAPIParser class directly or the public discover_api() method.