Changes to Physical gold — live country index

added the new optional query request parameter metal

added the non-success response with the status 400

added the non-success response with the status 422

the endpoint scheme security ApiKeyAuth was added to the API

the endpoint scheme security BearerAuth was added to the API

added the media type application/json for the response with the status 403

added the non-success response with the status 401

added the non-success response with the status 429

added the non-success response with the status 500

added the non-success response with the status 503