Add Infiniband GUID to well known Capabilities
Add Infiniband GUID to well known Capabilities

This commit extends CONVENTION.md Well-known Capabilities
to include `infiniband_guid`. this shall be used by CNI plugins
who wish to set Infiniband GUID address for a network interface.

Change-Id: I3716e0a9ea660937a73feee00ea9c5b1a92ab478
Signed-off-by: Adrian Chiris <de37a2b45e2f700b475699be94cf89a0f3b7d97c@mellanox.com>

appc/cni,containernetworking/cni,appc/cni,containernetworking/cni