Missing requirements and problems in Install section in README

[alexrjs]

I installed this exporter on my raspi zero 2 w. But I had to learn the hard way, that you need to install go and gcc before you can try to install. Also the install part assumes you have prometheus on the same machine. Also it assumes you have a node_exporter user, also not true if prometheus is not running on the same machine.

Would be nice to have a requirement info and what to configure if prometheus is running on a different host.

[d3vilh]

hey @alexrjs you can check pull requests there is Docker build and Docker compose image for ARM x64 are ready to go, so you don't need to build it manually.