The functionality of the former "CAP" and "SIGNAL" services is now provided by core's "PD" service.
Subsystems are now configured via .subsystem files in the VFS directory /subsystems. The adaption uses one <inline> node per subsystem.
This patch changes the top-level directory layout as a preparatory step for improving the tools for managing 3rd-party source codes. The rationale is described in the issue referenced below. Issue #1082