This patch is used for supporting the Flannel CNI in IEC project.
1. The flannel configuration file was add into cni/flannel/ folder.
2. CNI_TYPE variable was added in config file which is used for
choosing which type of CNI will be installed in IEC infrastructure.
3. The default value of CNI_TYPE is calico
Signed-off-by: Jingzhao.Ni <Jingzhao.Ni@arm.com>
Change-Id: I5a755ceaffd0e35f67cd4405a42bf67b4f6a28cd