Update website design

- Updated frameworks for better browser support
- Improved responsive design
- Versioned documentation
- Better social media support via the Jekyll SEO plugin
- New looks, fwiw
- Start page has some more relevant info
- Documentation sorted to be more easily accessible
- Internally upgraded from plain CSS to SASS

css/boxes.scss

@@ -0,0 +1,13 @@
+---
+# Front matter required for Jekyll to process this file
+---
+
+@import "overrides";
+
+@import "bootswatch-litera-4.6.0/variables";
+@import "bootstrap-4.6.0/bootstrap";
+@import "bootswatch-litera-4.6.0/bootswatch";
+
+@import "boxes";
+
+@import "perldoc";