Validate HTTP requests and responses against an OpenAPI v3.1 document

Changes for 0.050 - 2023-11-06T03:10:15Z

• fix construction of an OpenAPI::Modern object with a pre-constructed JSON::Schema::Modern::Document::OpenAPI object
• "recursive_get" moved from JSON::Schema::Modern::Document::OpenAPI to OpenAPI::Modern
• when validating header strings against a string schema, no longer parse out internal whitespace surrounding commas (validate as an array to use RFC9112 semantics).