Disable serializeImagePulls to speed up image pull

[zeroalphat]

What

By default, kubelet pulls container images in serial, and pulling a container image of a large size will cause other container images to wait to be pulled.
The kubelet configuration can be changed to pull container images in parallel, but this will result in an unlimited number of container image pulls.
If unlimited number of container images are pulled, disk IO and network bandwidth may be overloaded.

How

A setting called maxParallelImagePulls is added to kubernetes 1.27 to control the number of container images that can be pulled in parallel.
When we are finished with kubernetes 1.27, we will disable serializeImagePulls and configure maxParallelImagePulls.

Checklist

• Finish implementation of the issue
• Test all functions
• Have enough logs to trace activities
• Notify developers of necessary actions