Add metric for chaincode container build duration.

FAB-12868 #done

Change-Id: Ie28259ef3d6214616f6ef8d4eb5bbcdb13a4c599
Signed-off-by: Will Lahti <wtlahti@us.ibm.com>
Signed-off-by: Matthew Sykes <sykesmat@us.ibm.com>