UI Telegrafs: Extract and display required ENV options for the telegraf config as part of the install instructions

in many telegraf configs, the user uses environment variables to do substitution when telegraf starts. you can use these for INFLUX_TOKEN or INFLUX_ORG in many templates. https://github.com/influxdata/telegraf/blob/master/docs/CONFIGURATION.md#environment-variables

We should be able to extract that information and display it to the user when we show them the install instructions for a telegraf.

If there are environment variables in the configuration, then we should change step 2 to include those after setting the influx token.


Start by locating the UI code that renders Telegraf install instructions and the configuration extraction path, then review how environment-variable references are represented. Done means the displayed step 2 includes the configuration’s required environment variables when any are present, while preserving the existing instructions when none are found.

Written by the indexing model from the issue text.