Migrate WebConsole to Jakarta Servlet API

Once we have released all current changes for the webconsole. we can start with the migration of the webconsole to Jakarta Servlet API.
From a user perspective, this requires providing the Jakarta Servlet API as well as the OSGi Servlet Whiteboard implementation at runtime. For example Apache Felix Http Jetty 5.x does support this.
Apart from that no other changes should be required. Old plugins leveraging the javax servlet API should continue to run.
We could achieve this by a) changing the webconsole implementation itself to Jakarta Servlet API/Servlet Whiteboard and b) splitting up a compat package that support the javax servlet API and the old org.apache.felix.webconsole API