Reworked back-end with dynamic PHP Scripting

- Replaced all old HTML files with PHP scripts.
- Replaced most old HTML code with dynamic PHP tags
- Introduced dynamic headers (title, description, etc.). and dynamic
body tags.
- Most of the website is contained dynamically within index.html using
GET forms
- .htaccess rewritten to allow RewriteEngine, while still allowing
access to old .html files
- Added some snippets to projects page
- New icon!

TODO:
- Fix 403 and 404 redirection
- Add WordPress access