feat: allow configuring default OpenAPI info via properties

[egasimov]

Summary

• add a typed springdoc.api-docs.info configuration block so title, description, contact, license, version, summary, and vendor extensions can be supplied from YAML/properties
• have OpenAPIService populate missing Info metadata from those config values while still honoring user-provided OpenAPIDefinitions
• introduce OpenApiInfoFromYamlPropertiesTest plus a sample application-openapi-info.yml to verify the settings are read end-to-end

Testing

• mvn -pl springdoc-openapi-tests/springdoc-openapi-javadoc-tests -Dtest=OpenApiInfoFromYamlPropertiesTest test (blocked: Maven binary/mvnw unavailable in current environment)