Use the built-in utilities instead.

Also, add a warning in _root.scss so that we don't miss it again.

While important in the past, it has become obsolete, so removing it seems the best solution.

- `.carousel-caption` doesn't need a z-index. There are no non-static element in its containing block (`.carousel-item`)
- The `z-index` of `.carousel-indicators` is way higher than it needs to be (`15`), the highest sibling `z-index` is `1`, so it can be set to `2` to be the top layer.

- Add example to the new form control docs
- Reset the [list] selector in Reboot to hide the random dropdown arrow in Chrome

Kept `eslint@6.1.0` since the newer versions have a bug that affects us.

* Allow bundlesize to run for forks too.
* Add name for clone step.
* Add` fail-fast: false`

* Enable and fix all occurrences with no-mixed-operators rule
* Take care of the max-depth warning in button.js

Signed-off-by: mhatvan <markus_hatvan@aon.at>

* set `min-height` for `.form-control` textarea
  * prevent user from shrink textarea to minimum height