tests: add separate script for pulling in docker images
tests: add separate script for pulling in docker images

Have not measured, but expecting this to reduce at most a minute but
probably less when running the runtime tests.

Signed-off-by: Alexander Alemayhu <e46fc836cca3acec03944314d1457c2ae6c68ef3@alemayhu.com>

eloycoto/cilium,gumpt/cilium,michi-covalent/cilium,eloycoto/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,scanf/cilium,michi-covalent/cilium,mskarbek/cilium,gumpt/cilium,eloycoto/cilium,gumpt/cilium,cilium-team/cilium,gumpt/cilium,gumpt/cilium,scanf/cilium,gumpt/cilium,tklauser/cilium,tgraf/cilium,michi-covalent/cilium,scanf/cilium,michi-covalent/cilium,scanf/cilium,cilium/cilium,cilium/cilium,eloycoto/cilium,mskarbek/cilium,tgraf/cilium,scanf/cilium,mskarbek/cilium,eloycoto/cilium,mskarbek/cilium,gumpt/cilium,tklauser/cilium,mskarbek/cilium,tklauser/cilium,scanf/cilium,scanf/cilium,eloycoto/cilium,mskarbek/cilium,cilium-team/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,eloycoto/cilium,tgraf/cilium