linux build out of date

[RichNeese]

https://github.com/f4exb/sdrangel/wiki/Compile-from-source-in-Linux for one we have moved to soapysdr0.8 and most of it installed as modules only a few itels are not supported. next is /opt on linux is for the mostpart not used. need to work on a real install using the /usr/local for the extra parts. I will work on a script to fix alot but man we need to get this to use pkgs where it can I like sdrangle I use it on the mac . but on linux the flatpack is not working on arm64 and alot of us dont like docker for building when we can have more native installs .

This is the what most hams on debian and archlinux like