Fix SEO issue when links are not crawlable a#main-content for Vartheme BS5

Problem/Motivation

Lighthouse complains that a#main-content link is not crawable and it has a negative SEO impact, according to lighthouse.

Links are not crawlable
Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered.

Steps to reproduce

When running lighthouse and check the SEO rank.

Proposed resolution

Add add a href that links back to <a id="main-content"></a>

Google can follow your links only if they use proper tags with resolvable URLs

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ✅ Accessibility and Readability
• ✅ Code review from 1 Varbase core team member
• ✅ Full testing and approval
• ✅ Credit contributors
• ✅ Review with the product owner
• ✅ Update Release Notes and Update Helper on new feature change/addition
• ✅ Release varbase-10.0.0-alpha1 →
  , vartheme_bs5-1.0.0-rc2 →

Varbase update type

• ✅ No Update
• ➖ Optional Update
• ➖ Forced Update
• ➖ Forced Update if Unchanged

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• Issue #3275693 → by Mohammad Fayoumi → : Fixed SEO issue when links are not crawlable a#main-content for Vartheme BS5