Support Day2 operation: introduce a new CR to identify the Harbor instance to which the day2 operations are applying

[steven-zou]

Image rewriting rules / transparent proxy cache rules may be defined in this new CR.

Anyway to port the related info from HarborCluster CR to this new CR?

To see more info, please check poc project: https://github.com/szlabs/harbor-automation-4k8s

[lengrongfu]

@steven-zou Hi， Has this issue been resolved？