feat(plugins): implement plugin loading and management system

- Added PluginLoader component to dynamically load and initialize plugins.
- Created Plugins component for managing installed and marketplace plugins.
- Introduced PluginAPI for plugin interaction and settings management.
- Defined types for plugin metadata, installed plugins, and plugin index.
- Implemented settings rendering for plugins based on their schema.
- Integrated marketplace plugin fetching and installation logic.
- Added support for enabling/disabling and uninstalling plugins.

src/app/features/settings/plugins/index.ts

@@ -0,0 +1,4 @@
+export * from './Plugins';
+export * from './types';
+export * from './PluginLoader';
+export * from './PluginAPI';