Update documentation to use pipx for installing exo

[cyberbalsa]

I've found that installing exo using

pipx install git+https://github.com/exo-explore/exo.git

to be a much easier task then going to git clone + source install.sh route

its a simple change but would allow for newbies to get started quicker.

[AlexCheema]

It requires installing pipx though right? At this point we might as well have an install script. I was thinking we need a master install script that can install "hidden" dependencies like drivers and stuff.

[bentrnr21]

Thanks for help us