Implement custom docs template

[lampmaster]

It's a first approach; we will improve the docs template in the future (description, usage, and so on will be possible to add).

For now, the docs template contains only the following blocks:

• Name of the component
• Component
• Import example (now for both cases - webpack and ES module)
  • doesn't work in old storie format - story should have "component: Componen" field
• Controls with props description

Do not show all stories to the user.

[lampmaster]

also template.stories.tsx + template.mdx created (updated CONTRIBUTING.md) to have one source of truth and have one story format for every component