Accept serialized array and object path parameters

[ydah]

OpenAPI 3 path arrays and objects serialized with simple, label, or matrix style are validated while still strings. For example, /paths/1,2 is rejected as a String instead of being validated as [1,2]. Deserialization happens later, and exploded matrix arrays remain one raw string.

Deserialize path values before passing them to openapi_parser for validation and coercion, including parameters declared on path items. Parse repeated matrix segments such as ;ids=1;ids=2 into separate elements.

[geemus]

@ydah could you resolve the conflicts on this one? The test one seems clear enough, but I'm feeling less confident on properly reconciling the validator. Thanks.