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 +1,16 @@
+---
+title: 'High Flight Network Operating Company (HFNOC) - Business/Operations/Product Plan - Introduction
+'
+menu: 'High Flight Network Operating Company (HFNOC) - Business/Operations/Product Plan - Introduction
+'
+---
+
+# High Flight Network Operating Company (HFNOC) - Business/Operations/Product Plan - Introduction
+
+## Executive Summary for HFNOC
+
+HFNOC runs the network , launch facilties etc.
+
+## Reduction to practice
+
+- [GIT Organization](https://git.knownelement.com/HFNOC)