Feature request: API to see how many invocations of a trigger remain

When creating a trigger a developer can specify a `maxTriggers` parameter. If one isn't supplied, the trigger will run 1,000 times. The upper limit is 10,000 invocations.

Currently the `wsk trigger get` CLI command does not show how many invocations remain. Can this be enhanced to show the maxTriggers set at creation time, and how many remain?

This would give the developer a way to delete/recreate the trigger programmatically if needed when it's anticipated that the trigger is approaching its "end of life."