Refresh Linux install and install fwup via asdf

[fhunleth]

This moves the Linux distro-specific parts to tabs to reduce the amount of text the user sees. It installs a little more in the first package installation line to cover packages the user may need for building Erlang and fwup as well.

The big change for Debian and Fedora users is to use asdf to install fwup which should be easier than the current build-from-sourse instructions.

Here's what it looks like: