* [SPE-6] Boundary vs. other software * Minor edit for word choice * Update navigation * Change redundant word in nav * Fix broken links * Add anchor link * Copy edits * Nest navigation for What is Boundary? section * Apply batch suggestions from code review Co-authored-by: Adam Bouhmad <adbouhmad@gmail.com> * Update intro sentence with new wording * Split sections out into topics * changes title of Introduction -> Overview to What is Boundary? * adds redirects for use-cases and what-is-boundary Co-authored-by: Adam Bouhmad <adbouhmad@gmail.com> Co-authored-by: stellarsquall <stellarsquall@protonmail.ch>