Rename DynamicDependerModuleContext to BaseModuleContext

DynamicDependerModuleContext is really a base module context used
by multiple types of ModuleContext interfaces.  Rename it to
BaseModuleContext, and create a new DynamicDependerModuleContext
that just wraps it.

Change-Id: Ibb402e1d680d50ed15d6548e99b32cc0b5b52b12