* remove un-needed gomod replaces
* add a make target gomodtidy
* update docs on using gomodtidy
* add automation to run go mod tidy on every push
* update contributing docs to be more helpful
* install gopogh if it is not installed in html_report
* addres PR reviews
* update docs headings
Testing shows that we need changes changes:
- x86_64 cpu
- Ubuntu 22.04
- docker is required even if building without docker
- python2 instead of python
- genisoimage (for mkisofs)
- Installing Go manually (Ubuntu 22.04 have only Go 1.18)
- Target should be minikube-iso-aarch64 or minikube-iso-x86_64. Using
arm64 and amd64 fails.
I also cleaned up a little bit the formatting to make it easier to
maintain (one package per line).
Tested building:
- minikube-iso-aarch64
- minikube-iso-x86_64
I did not test the built iso images.