- Added new base_colors associative array for color definitions.
- Implemented zrep_load_theme function to load themes.
- Modified zrep_msg function to use colors from the current theme.
- Updated zrep_version function to use theme colors for help and info.
- Adjusted zrep_list_installed_packages to use base_colors for color definitions.
- Enhanced zrep_update_package with informative messages.
- Added zrep_download_package function for downloading packages.
- Improved zrep_install_package to use zrep_download_package for downloads.
- Updated main function to load the global theme.
