ContainerAssembler scope parameter as Object

The integration kit package defines the ContainerAssembler concept, which is responsible for assembling a PicoContainer based on a scope. This enhancement proposes to change the scope parameter type from String to Object.

Rationale:
In the servlet pico-extras sub-project, scopes used are "application", "session" and "request". Chaning scopes to ServletContext, HttpSession and HttpRequest, would facilitate (if not make possible?) integration with legacy code tied to the servlet environment.

Example:
Wrapping OSCache in a pico component to use in WW2 actions. OSCache needs ServletContext, which is not available at container assembly. If scope was ServletContext, it would be possible.