feat: add markdown links checker workflow

[jaybxyz]

Description

This PR adds markdown link checker workflow to check all Markdown files for broken links every 24 hours.

closes: #138

Tasks

• Add linkchecker.yml
• Fix broken links

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• Appropriate labels applied
• Targeted PR against correct branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration
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• Added relevant godoc comments.
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• Review Codecov Report in the comment section below once CI passes

[codecov]

Codecov Report

Merging #139 (4044c61) into master (85846ba) will not change coverage.
The diff coverage is n/a.

❗ Current head 4044c61 differs from pull request most recent head d0b85e6. Consider uploading reports for the commit d0b85e6 to get more accurate results

@@           Coverage Diff           @@
##           master     #139   +/-   ##
=======================================
  Coverage   69.71%   69.71%           
=======================================
  Files          25       25           
  Lines        2262     2262           
=======================================
  Hits         1577     1577           
  Misses        533      533           
  Partials      152      152           

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