feat: convert from mdbook to Grav format

- Rename src/ to pages/
- Add Grav frontmatter to markdown files
- Create numbered folder structure
- Remove mdbook-specific files

Migration from mdbook to Grav CMS.

pages/01.home/default.md

@@ -0,0 +1,18 @@
+---
+title: 'TSYS Group'
+menu: 'TSYS Group'
+---
+
+# TSYS Group
+
+## Executive Summary
+
+TSYS Group or "TSYS" is the shorthand we use to refer to the entire collection of components that support the overall mission.
+
+## Reduction to practice
+
+- [TSYS Group Governance Portal](https://governance.turnsys.com/)
+- [TSYS Group Non Profit Portal](https://nonprofit.turnsys.com/)
+- [TSYS Group Charters](https://charters.turnsys.com/)
+- [TSYS Group Stakeholder Relations](https://sr.turnsys.com/)
+- [TSYS Group Handbook](https://handbook.turnsys.com/)