[Kapacitor list task API] fields query parameter is not working for template-id

Hi,

I am trying to get `template-id` for all tasks on listing task API.
I tried `/kapacitor/v1/tasks?fields=template-id` API but it's throwing error with `"unsupported field \"template-id\""`. Though `template-id` is a valid field for a task it's not returning expected response. It's working fine with other fields. I see there is a issue #1368 which talks about the API. Don't know whether it's in pipeline for next release or not?

I am using kapacitor latest docker image.

Start by reproducing /kapacitor/v1/tasks?fields=template-id with the latest Docker image and trace the task-list API handling for requested fields. Done means the request no longer reports "unsupported field \"template-id\"" and returns template-id for listed tasks.

Written by the indexing model from the issue text.