Implements jeaddons CLI tool

Adds a CLI tool to copy files or folders from a git repository into the current project based on a registry.

The tool provides commands to:
- `add`: Copies files/folders based on registry entries.
- `list`: Lists available registry entries.

Registry entries are defined in `jeAddons/registry.py`.
The tool supports overriding the registry's ref and destination.

.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/jeAddons.iml" filepath="$PROJECT_DIR$/.idea/jeAddons.iml" />
+    </modules>
+  </component>
+</project>