Create Dispatch implementation that is configurable via service.xml file

Create a org.apache.knox.gateway.dispatch.Dispatch implementation that is configurable via metadata file (for example, service.xml). Configurable parameters should be

• headers to exclude when forwarding requests
• whether parameters should URL-encoded or not

Such an implementation should be able to make at least the following Dispatch implementations obsolete:

• org.apache.knox.gateway.dispatch.PassAllHeadersNoEncodingDispatch
• org.apache.knox.gateway.dispatch.PassAllHeadersDispatch

A possible declaration could be:

    <dispatch classname="org.apache.knox.gateway.dispatch.ConfigurableDispatch">
       <property>
           <name>excludeHeaders<name>
           <value>Authorization,Content-Length</value>
       </property>
       <property>
           <name>removeUrlEncoding<name>
           <value>false</value>
       </property>
    </dispatch>

Or maybe

    <dispatch classname="org.apache.knox.gateway.dispatch.ConfigurableDispatch" removeUrlEncoding="true" excludeHeaders="Authorization, Content-Length" />