fix(markdown-navigator): add conf to render covalent and material-icons

[omaardev]

Description

Add all icon configurations to support covalent and material icons in component

What's included?

• Support for covalent and material icons

Test Steps

• npm run start
• then navigate to markdown-component
• the markdown example have icons from covalent and material

General Tests for Every PR

• npm run start still works.
• npm run lint passes.
• npm run stylelint passes.
• npm test passes and code coverage is not lower.
• npm run build still works.

Screenshots or link to StackBlitz/Plunker

Before

After