Factorize all Web Container resources in a single Servlet that uses Extension point

Nuxeo Web Layer is currently built using Servlets, Filters and Listeners.
Because JEE descriptors are monobloc, we had to introduce deployment fragments and pre-processing so that we generate at startup the web.xml, faces-config.xml ...

This solution works so far, but has some limitations :

• in pure OSGi we can not use this because only servlets are supported

• the deployment system has to be adapted to the target deployment (and currently ECR and Nuxeo use different solutions)

• the web.xml is hudge and we have a lot of fragments, but no tool to have a simple global vision of what filters are applicable to a given urls

• web.xml bindings are limited because there is no clean support for regexp

So the idea would be to extend what has been done in ECR :

• have one big servlet

• that supports extensions points to bind filters, listeners and servlets

• contains all the routing / activation code

Having this would make pure OSGi deployment of the web layer easier and would also make JEE deployment simplier and easier to port to additionnal deployment targets.