Rice-manager

**Fixes:**
- GTK theme applying on launch

**Implemented:**
- Text icon replacement with Gio Icons
- Notifications for applying themes and removing rices

**Introduces:**
- GTK theme selector on the main menu 🥳

**Introduces:**
- CSS styling
- local python interpreter with PyGObject builtin

**Fixed:**
- Dotfiles from every rice linking upon rice application 😬
- Unlinking of previous rices on rice application

**Implemented:**
- Remove symlink box for unlinking dotfiles
- Confirmation box for removal of rices

**Fixed:**
- Dotfile preview not being scrollable

**Fixes:**
- Issue where all rice pages would disappear from the rice viewer
- neatened code (show_about_dialog especially)

**Fixes:**
- Multiple file select when adding dotfiles
- Made about menu icon smaller