DISCOVERY: Add difficulty badges on articles

[azinit]

Description

• With UI-tags by types: Beginner, Intermediate, Advanced

  • With preliminary articles indexing
    

• Feel free to inspire by other docs examples

• Feel free to use "built-in" docusaurus tags-styles

  <span class="badge badge--primary">Primary text</span>
  <span class="badge badge--secondary">Secondary text</span>
  <span class="badge badge--success">Success text</span>
  <span class="badge badge--danger">Danger text</span>
  <span class="badge badge--warning">Warning text</span>
  <span class="badge badge--info">Info text</span>
  <span class="badge badge--light">Light text</span>
  <span class="badge badge--dark">Dark text</span>

Difficulty map

See at inner miro