MANAGER: Make AH available as a descriptor

Part of #6.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Change AFF prototype so it looks more like the implementation

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Better match between prototype and implementation for AH

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Add missing module import and print out signal metadata

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
DESCRIPTORS: Add AH descriptor sources

Part of #6.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>