This requires the following changes:
1. We need to pass in -ldflags to `go test`, since we need to know the curren iso version to correctly generate the description for --iso-url
2. We need to rewrite the description of the --driver flag on `minikube start` because it is operating system specific, which doesn't make sense for our documentation
Now, generate-docs will compile all subcommands for one command into one document instead of creating a document per subcommand.
For example, instead of creating:
minikbue_addons_enable.md
minikbue_addons_disable.md
it will now create
addons.md
which will include subsections for `minikube addons enable` and `minikube addons disable`.