User specified parameters for container info.

In this PR, we allow api users to specify how many stats/samples they want to retrieve and also let them to specify which percentile of CPU/Memory usage they want to retrieve.


These tests are getting unmanageable :( I think it's fine for this PR, but lets re-think what we need to make better tests. Needing to pass a function to a function to a function can't be what we should be doing.