Extracts an API key from a URL query parameter. By default, the parameter name
is {@code api-key}. If the parameter is present in the request URI, its value is returned as the API key.
Parameter name matching is case-insensitive.
Example usage inside {@code <apiKey>}:
<apiKey>
<queryParamExtractor />
<queryParamExtractor name="api_key"/>
</apiKey>