This reverts commit 8668677a01100d22e6799ce3f73f58b92a1b030c and 82fba05c62d5a5036455fa936cfa045f60b4724c

Re-introducing lazy loading is a bad idea.
Bug 1096332 - All content-related workflows broken on Agent

All *ContextImpl classes now user eagerly loaded plugin container services

The content subsystem was the only one affected as:
* some of the other managers were created and initialized before the inventory manager
* some of the *ContextImpl classes were still lazy loading container services