add QoL features: tags, social embed, better search, improved toc

[wizzdom]

adds various quality of life features:

• tags
• social embed - embeds now have an auto-generated image for each page
• improved search - search query is highlighted on pages and suggestions are better, using tags
• table of contents now follows as you scroll and is integrated into site navigation on the left
• headings now have anchor links allowing permalinks to specific sections
• fixes poor table formatting
• fixes broken external links
• use requirements.txt instead of a long pip install command, following best practices
• logo now bounces on page load