Convert component examples to mdx

[rvsia]

• Component pages are converted into MDX
• Header is set in the MDX, not in the component itself

Should help Algolia to crawl these pages

[codecov]

Codecov Report

Merging #279 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #279   +/-   ##
======================================
  Coverage    85.5%   85.5%           
======================================
  Files          95      95           
  Lines        1863    1863           
  Branches      620     620           
======================================
  Hits         1593    1593           
  Misses        270     270

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[Hyperkid123]

🎉 This PR is included in version 1.25.2 🎉

The release is available on

• react-form-renderer (@latest dist-tag)

• pf3-component-mapper (@latest dist-tag)

• pf4-component-mapper (@latest dist-tag)

• mui-component-mapper (@latest dist-tag)

Demo can be found here!