Maps contentMediaType values to SchemaContentType for content-encoded
string schemas. When a schema has contentEncoding set, this config
determines whether it generates a StringModel or a binary-backed model.
Binary mappings and unmatched media types generate a Base64Model for
base64 content and a BinaryModel for other encodings.
Maps media type strings to ContentType for parsing request/response bodies.
Default includes 'application/json' only. Add custom JSON-like media types
(e.g., 'application/hal+json': ContentType.json) via configuration.