Re-categorized accessing backend docs under Misc, removed old message…

[markshust]

… about <2.4.6

[what-the-diff]

PR Summary

• Updated Magento Backend Access Instructions
  An obsolete section that provided instructions on how to access the Magento backend was eliminated. This included details such as how to login using default credentials and guidelines on Two-Factor Authentication (2FA).

• Revised and Repositioned Backend Access Content
  The same instructions on accessing the Magento backend have been re-introduced. However, this information has been rearranged within the document, potentially for better understanding and user flow.

• Removed Version-Specific Installation Comments
  Previously, the document had specific comments for installing Magento versions prior to 2.4.6 that outlined setup instructions for Elasticsearch. These comments have now been removed, which might simplify the current installation process.