Setup for Linux: Curl should be installed before first command

[CornaSn]

In Ubunutu curl is not installed. Must be installed before you can use first command.

https://github.com/upleveled/system-setup/blob/main/linux.md

[karlhorky]

Thanks for the report!

@ProchaLu @Eprince-hub looks like we'll need a 1st PR to add a new command at the beginning of the Linux System setup guide sudo apt-get install -y curl

2nd PR: Although it seems like in modern resources, apt-get has changed to apt eg. sudo apt install -y curl

• https://www.cyberciti.biz/faq/how-to-install-curl-command-on-a-ubuntu-linux/
• https://serverfault.com/questions/1153864/can-i-rely-on-curl-being-installed-on-debian-ubuntu-how-could-i-find-out

So let's do a 2nd PR to fix all usages of apt-get to use apt instead.