Allow altering components created elsewhere

Problem/Motivation

Imagine Acme corp, a Drupal agency. They have a component library that they reuse across projects. In there they have accessible components with very sober styling. All those components are packaged in a custom Drupal module acme/acme_base_components.

They use the components in their theme as usual. For instance in the node--article--card.html.twig they have a section with:

{# ... #}
{% include "@acme_base_components/components/acme-button/acme-button--primary.twig" with {
  text: 'Click Me',
  iconType: 'external'
} %}
{# ... #}

However in their project for Client Inc. they need to tweak the styles, JS, or markup a tiny bit.

Acme should be able to add a component acme-button in the theme for Client Inc. that extends the base acme-button.

Proposed resolution

Take inspiration from component shadowing in Gatsby, or other technologies to propose a solution.

After some discussion in #3050386: Allow loading CSS and JavaScript directly from templates, and in video-chat, we have decided to only support forking/replacing components. If more granularity is needed, one can split the component further to allow overriding each one of the pieces.

The reasoning is that extending components imposes unreasonable maintenance burden on the original component side (core, contrib, etc).

For simplicity, only one component can extend/decorate another.