swarmctl: Dummy `task ls` implementation to try out scheduling
swarmctl: Dummy `task ls` implementation to try out scheduling

Signed-off-by: Andrea Luzzardi <442ffe3ffbfd024afcf0b7f8b108d05bca3aae43@gmail.com>

jlhawn/swarmkit,AliyunContainerService/swarmkit,vasil-yordanov/swarmkit,docker/swarmkit,alyyousuf7/swarmkit,aaronlehmann/swarmkit,cezarsa/swarmkit,yongtang/swarmkit,cheyang/swarmkit,Noyan759/swarmkit,alyyousuf7/swarmkit,dperny/swarmkit-1,cheyang/swarmkit,cezarsa/swarmkit,deljuven/swarmkit,AliyunContainerService/swarmkit,elifa/swarmkit,vasil-yordanov/swarmkit,allencloud/swarmkit,docker/swarmkit,yp-engineering/swarmkit,yp-engineering/swarmkit,fate-grand-order/swarmkit,yongtang/swarmkit,diogomonica/swarmkit,runshenzhu/swarmkit,dperny/swarmkit-1,deljuven/swarmkit,elifa/swarmkit,RenaudWasTaken/swarmkit,sungwonh/swarmkit,runshenzhu/swarmkit,sungwonh/swarmkit,Noyan759/swarmkit,jlhawn/swarmkit,RenaudWasTaken/swarmkit,diogomonica/swarmkit,fate-grand-order/swarmkit,allencloud/swarmkit,aaronlehmann/swarmkit