Support `os/arch` param

[ethan256]

Issue Description

Type: feature request

Describe what feature you want

Synchronize only the mirrors of the specified os and arch. example:

./image-syncer --arch=amd64 --arch=arm64 --os=linux --proc=4 --auth=./auth.yaml --images=./images.yaml --retries=3

The above commands only synchronize linux/amd64 and linux/arm64 images.

Additional context