write a plugin guide for vxlan

Signed-off-by: ynojima <mail@ynojima.net>
Signed-off-by: Prasanna Santhanam <tsp@apache.org>
Adding cloudstack brand directory
VxLan: Missing publican config file

Signed-off-by: Prasanna Santhanam <tsp@apache.org>
write a plugin guide for vxlan

Signed-off-by: ynojima <mail@ynojima.net>
Signed-off-by: Prasanna Santhanam <tsp@apache.org>
CLOUDSTACK-3243 fixed the mount point errors
Add section to describe VNI allocation matter