[examples] copy resnet example to image (#4090)

* copy resnet example

* add pytest package

* skip test_ci

* skip test_ci

* skip test_ci

examples/images/resnet/test_ci.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -xe
+
+export DATA=/data/scratch/cifar-10
+
+pip install -r requirements.txt
+
+# TODO: skip ci test due to time limits, train.py needs to be rewritten.
+
+# for plugin in "torch_ddp" "torch_ddp_fp16" "low_level_zero"; do
+#     colossalai run --nproc_per_node 4 train.py --interval 0 --target_acc 0.84 --plugin $plugin
+# done