message: docs: write on how to use feature flags within templates
diff: @@ -254,6 +254,43 @@ use `ui:widget: password` or set some properties of `ui:backstage`:
  show: false # wont print any info about 'hidden' property on Review Step
  ```
  +### Remove sections or fields based on feature flags
  +
  +Based on feature flags you can hide sections or even only fields of your
  +template. This is a good use case if you want to test experimental parameters in
  +a production environment. To use it let's look at the following template:
  +
  +```yaml
  +spec:
  + type: website
  + owner: team-a
  + parameters:
  + - name: Enter some stuff
  + description: Enter some stuff
  + backstage:featureFlag: experimental-feature
  + properties:
  + inputString:
  + type: string
  + title: string input test
  + inputObject:
  + type: object
  + title: object input test
  + description: a little nested thing never hurt anyone right?
  + properties:
  + first:
  + type: string
  + title: first
  + backstage:featureFlag: nested-experimental-feature
  + second:
  + type: number
  + title: second
  +```
  +
  +If you have a feature flag `experimental-feature` active then
  +your first step would be shown. The same goes for the nested properties in the
  +spec. Make sure to use the key `backstage:featureFlag` in your templates if
  +you want to use this functionality.
  +
  ### The Repository Picker
  In order to make working with repository providers easier, we've built a custom
  