Move development documentation under docs/development

The Development section holds more than one page and will grow further,
so give it its own directory. development.md becomes development/index.md,
which keeps its published URL, and the custom CLI command page moves
alongside it.

Update the nav, the cross-link between the two pages, and the README
link to the custom command documentation, which is now published at
/development/custom_commands/.

README.md

@@ -84,7 +84,7 @@ details.
 
 Users can also add top-level commands to `mvt-ios` and `mvt-android` from
 installed Python packages or local files and folders. See the
-[custom CLI command documentation](https://docs.mvt.re/en/latest/custom_commands/)
+[custom CLI command documentation](https://docs.mvt.re/en/latest/development/custom_commands/)
 for the plugin entry points and `--load-command` interface.
 
 

docs/development/custom_commands.md

@@ -1,7 +1,7 @@
 # Custom CLI Commands
 
 MVT can load additional top-level commands into `mvt-ios` and `mvt-android`.
-Custom commands are different from [custom forensic modules](development.md#custom-modules):
+Custom commands are different from [custom forensic modules](index.md#custom-modules):
 commands add new CLI operations, while modules add analysis steps to existing
 `check-*` commands.
 

mkdocs.yml

@@ -50,6 +50,6 @@ nav:
         - Check Android Intrusion Logs: "android/intrusion_logs.md"
     - Indicators of Compromise: "iocs.md"
     - Development:
-        - Development Instructions: "development.md"
-        - Custom CLI Commands: "custom_commands.md"
+        - Development Instructions: "development/index.md"
+        - Custom CLI Commands: "development/custom_commands.md"
     - License: "license.md"