Model version management

[kerthcet]

What would you like to be added:

Right now, we only have one model version for common deployment, however, if we take a higher level view of the model lifecycle, version management is necessary.

Why is this needed:

Support the full lifecycle of models.

Completion requirements:

This enhancement requires the following artifacts:

• [x] Design doc
• [x] API change
• [x] Docs update

The artifacts should be linked in subsequent comments.

[kerthcet]

/kind enhancement

[kerthcet]

However, we should wait for real feedbacks from our users in the future. /priority important-longterm