Define Certificate CRD for Auto TLS #3050
Description
Expected Behavior
As part of work in #1964, we need to define a internal CRD Certificate to make TLS provision more pluggable.
When a Certificate object is created, it is expected that the Certificate Controller requests a SSL certificate according to the information of the Certificate object.
Actual Behavior
No such CRD
Additional Info
For more information about auto TLS, see design doc