lxd/containers/get: Makes /1.0/containers filter by instance type container
lxd/containers/get: Makes /1.0/containers filter by instance type container

- However there is still work to do in doContainersGetFromNode and doContainersFullGetFromNode to actually filter, however this requires changing the client package.

Signed-off-by: Thomas Parrott <311bb6b467675b937a24a1860d8fd7780626c535@tomp.uk>

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