Support multi arch image

[zhouqiang-cl]

A prospect has this question:

out of curiosity, why are the ARM64 Docker images published as a separate repo (pingcap/tidb-arm64, for example) instead of under the main repo (pingcap/tidb) with a multi-arch manifest?

the "typical" way to do this is to publish arch-specific images using tags (pingcap/tidb:v5.2.3-arm64) and then have the non-arch-suffixed tag (pingcap/tidb:v5.2.3) be a manifest pointing to the arch-specific images. this lets you just specify the non-arch-suffixed image tag (like you already do now for AMD64) and have the container engine automatically pull the correct image for your arch