Update the sections and merge subpages of the documentation

[Ludee]

Summary of the discussion

Update the sections and merge subpages of the documentation.

Type of change (CHANGELOG.md)

Changed

• Update the sections and merge subpages of the documentation (#62)

Removed

• Remove merged documentation files (#62)

Workflow checklist

Automation

Closes #4

PR-Assignee

• 🐙 Follow the workflow in CONTRIBUTING.md
• 📝 Update the CHANGELOG.md
• 📙 Update the documentation

Reviewer

• 🐙 Follow the Reviewer Guidelines
• 🐙 Provided feedback and show sufficient appreciation for the work done