Style API: plugin manager and definition, form element

Problem/Motivation

Initially handled in #3517033: Add a style utility API.

As the goal is to split the issue into smaller with reduced scope, I create this issue.

Regarding MR https://git.drupalcode.org/project/drupal/-/merge_requests/13379

This issue's scope is about:

• core/assets/schemas/v1/style.schema.json
• core/lib/Drupal/Core/Render/Element/Styles.php
• core/lib/Drupal/Core/Theme/Style
  • core/lib/Drupal/Core/Theme/Style/StyleDefinition.php: some parts
• core/modules/system/system.styles.yml
• related tests

Improving the plugin discovery by splitting into two files:
- *.utilities.yml
- *.themes.yml

Instead of *.styles.yml. Let the type property be automatically set by the detected name.