feat: Major updates to backend structure and security enhancements

- Removed `COMMON_ERRORS.md` file to streamline documentation.
- Added `Flask-Limiter` for rate limiting and `redis` for session management in `requirements.txt`.
- Expanded `ROADMAP.md` to include completed security features and planned enhancements for version 2.2.
- Enhanced `setup_myp.sh` for ultra-secure kiosk installation, including system hardening and security configurations.
- Updated `app.py` to integrate CSRF protection and improved logging setup.
- Refactored user model to include username and active status for better user management.
- Improved job scheduler with uptime tracking and task management features.
- Updated various templates for a more cohesive user interface and experience.

backend/app/node_modules/postcss/README.md

@@ -0,0 +1,28 @@
+# PostCSS
+
+<img align="right" width="95" height="95"
+     alt="Philosopher’s stone, logo of PostCSS"
+     src="https://postcss.org/logo.svg">
+
+PostCSS is a tool for transforming styles with JS plugins.
+These plugins can lint your CSS, support variables and mixins,
+transpile future CSS syntax, inline images, and more.
+
+PostCSS is used by industry leaders including Wikipedia, Twitter, Alibaba,
+and JetBrains. The [Autoprefixer] and [Stylelint] PostCSS plugins is one of the most popular CSS tools.
+
+---
+
+<img src="https://cdn.evilmartians.com/badges/logo-no-label.svg" alt="" width="22" height="16" />  Made at <b><a href="https://evilmartians.com/devtools?utm_source=postcss&utm_campaign=devtools-button&utm_medium=github">Evil Martians</a></b>, product consulting for <b>developer tools</b>.
+
+---
+
+[Abstract Syntax Tree]: https://en.wikipedia.org/wiki/Abstract_syntax_tree
+[Evil Martians]:        https://evilmartians.com/?utm_source=postcss
+[Autoprefixer]:         https://github.com/postcss/autoprefixer
+[Stylelint]:            https://stylelint.io/
+[plugins]:              https://github.com/postcss/postcss#plugins
+
+
+## Docs
+Read full docs **[here](https://postcss.org/)**.