Readme overhaul (download script added) and firefox policy added for security

main: sudo check uses == instead of -eq now
readme: download instructions added
readme: download folder updated
readme: directory corrected
readme: running doesn't need to be executable, use bash instead
fedora: starship fix
shared: comment to run omf install bobthefish removed, it will only ask to exit now
readme: updated to list commands for stable and experimental install
added option to copy firefox policies, starship changed to first option when choosing shells
shared: starship is default
shared: fish on top instead of zsh
shared: starship option as first, all: usergroups added before setups(fix for opensuse's flatpak)
shared: starship as last to setup all shells, readme: firefox policy copy updated script
shared: better postcss extension added
readme: better code shown
readme: bold fixed
readme: links to the readmes of distros added
shared: seperate script for installing starship for debian and fedora
debian and fedora: starship-install before shell setups
fedora: starship install fixed
debian and fedora starship new fix
debian: fish removed from default packages
debian and fedora: fixed typo
debian and fedora: starship detection fixed
debian and fedora: starship detection fixed, stars outside

closes #68

KnightTheCoder / Linux-Distro-Post-Install-Scripts