Update the Telegraf Plugin Types

[This PR](https://github.com/influxdata/openapi/pull/125) reverted some explicit types that a telegraf plugin should have. The reason for the revert was that there the UI sets additional definitions for the plugin types, and that discrepancy was causing issues when updating the SHA. We should set the telegraf plugin types in one place, and use that as a centralized source of truth (whether that means adding the plugin types from the UI to the API, or removing those additional types from the UI). Regardless of the outcome, the yaml should be the source of truth for the UI and API in order to resolve any conflicts later on

Start by reviewing PR 125 and the Telegraf plugin type definitions in the YAML, then compare them with the additional definitions used by the UI. Done means the plugin types have one centralized source of truth in the YAML and the UI and API no longer diverge when the SHA is updated.

Written by the indexing model from the issue text.