Blocking call to start feast ingestion job

[zhilingc]

Is your feature request related to a problem? Please describe.
It would be very useful to have the option to start an ingestion job in a blocking fashion, terminating only when the job has reached a terminal state. This is particularly helpful when starting jobs from an automated pipeline.

Describe the solution you'd like
This can be baked into the CLI/SDKs - just add an additional flag. The core API is fine as is since the get job endpoint returns the job state.

[tims]

Will this just poll for status on the client side?

[zhilingc]

Yep. I've implemented it on the CLI, will make the PR when i've tested it