This PR refactores the StrategyVariants component to be passed in from
the outside to the new form component. This allows us to pass in the
StrategyVariants with an "editable" property in the create form which we
use to determine the editable state of the name input field. If the
editable field is not passed in we keep the old behavior.
Notable changes:
* StrategyVariants is now passed in from the outside, allowing us to
define different props at call time
* Added tests for the new behavior, and for keeping the old behavior
(such as in edit strategy)
* Added tracking
This PR sets up the variants tab for the new strategy configuration.
Also some minor adjustments to the new form:
* Change where padding is controlled to allow us to have more granular
control over how the buttons width and border should look and have the
tabs have full-width borders across the form
* Move the buttons to be absolutely positioned at the bottom of the page
* Move where we display banners to avoid clutter
<img width="1284" alt="Skjermbilde 2023-12-14 kl 21 17 53"
src="https://github.com/Unleash/unleash/assets/16081982/45e6a364-e4aa-47ac-b420-f3be9b39a15e">
