lxd/network: Adds network type in network pkg
lxd/network: Adds network type in network pkg

Also adds n.HasDHCPv4() and n.HasDHCPv6() functions to indicate whether DHCP server is enabled for the network.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

stgraber/lxd,hallyn/lxd,Skarlso/lxd,atxwebs/lxd,Skarlso/lxd,lxc/lxd,lxc/lxd,stgraber/lxd,Skarlso/lxd,stgraber/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,atxwebs/lxd,lxc/lxd,hallyn/lxd,lxc/lxd,atxwebs/lxd,stgraber/lxd,atxwebs/lxd,stgraber/lxd,mjeanson/lxd,hallyn/lxd,Skarlso/lxd,mjeanson/lxd,hallyn/lxd,lxc/lxd,mjeanson/lxd,lxc/lxd,lxc/lxd