Implement ViewIt Plugin System Documentation and Update Project Notes

- Added comprehensive documentation for the ViewIt Plugin System, detailing the plugin loading process, required methods, optional features, and community extension workflow.
- Updated project notes to reflect the current structure, build process, search logic, and known issues.
- Introduced new build scripts for installing the add-on and creating ZIP packages.
- Added test scripts for TMDB API integration, including argument parsing and logging functionality.
- Enhanced existing plugins with improved search logic and error handling.

addon/NOTICE.txt

@@ -0,0 +1,13 @@
+Copyright (C) 2026 ViewIt contributors
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+This Kodi addon depends on `script.module.resolveurl`.