functional tests: Add quay server type
functional tests: Add quay server type

It asks to defer the signature file download until the image is
downloaded first.

joshix/rkt,alban/rkt,mike1729/rkt,yifan-gu/rocket,sstabellini/rkt,markllama/rkt,kbrwn/rkt,yifan-gu/rocket,kinvolk/rkt,Shashwatsh/rkt,intelsdi-x/rkt,yifan-gu/rkt,Shashwatsh/rkt,endocode/rkt,sinfomicien/rkt,endocode/rkt,rkt/rkt,markllama/rkt,blixtra/rkt,kbrwn/rkt,monstermunchkin/rkt,euank/rkt,sgotti/rkt,markllama/rkt,squeed/rkt,sgotti/rkt,Wilybald/rkt,rkt/rkt,squeed/rkt,matthaias/rkt,kinvolk/rkt,s-urbaniak/rkt,nhlfr/rkt,linki/rkt,lucasallan/rkt,il9ue/rkt,nhlfr/rkt,joshix/rkt,cab105/rkt,intelsdi-x/rkt,jonboulle/rkt,yifan-gu/rkt,akshaykarle/rkt,s-urbaniak/rkt,s-urbaniak/rkt,nhlfr/rkt,kinvolk/rkt,blixtra/rkt,akshaykarle/rkt,sstabellini/rkt,matthaias/rkt,jakon89/rkt,rkt/rkt,blixtra/rkt,intelsdi-x/rkt,il9ue/rkt,squeed/rkt,Wilybald/rkt,shobhit85/rkt,euank/rkt,ybubnov/rkt,yifan-gu/rocket,matthaias/rkt,jakon89/rkt,coreos/rkt,monstermunchkin/rkt,jjlakis/rkt,tmrts/rkt,il9ue/rkt,sinfomicien/rkt,achanda/rkt,dgonyeo/rkt,Wilybald/rkt,shobhit85/rkt,achanda/rkt,alban/rkt,cab105/rkt,sstabellini/rkt,mike1729/rkt,dgonyeo/rkt,ybubnov/rkt,monstermunchkin/rkt,joshix/rkt,dgonyeo/rkt,sgotti/rkt,Shashwatsh/rkt,jjlakis/rkt,jonboulle/rkt,euank/rkt,mike1729/rkt,jakon89/rkt,kbrwn/rkt,endocode/rkt,tmrts/rkt,sinfomicien/rkt,jonboulle/rkt,coreos/rkt,lucasallan/rkt,joshix/rkt,Wilybald/rkt,coreos/rkt,lucasallan/rkt,rkt/rkt,jjlakis/rkt,tmrts/rkt,kinvolk/rkt,linki/rkt,shobhit85/rkt,akshaykarle/rkt,lucasallan/rkt,alban/rkt,yifan-gu/rkt,linki/rkt,cab105/rkt,ybubnov/rkt,achanda/rkt