kata-manager is introduced in the install documentation as an easy way to install kata for new users.

At the moment, there are some prerequisites needed to get kata-manager working:

• have git and the golang installed
• have a copy of kata-doc-to-script.sh available in ${GOPATH}/src/${test_repo}/.ci/

It's unlikely that new users have their system setup in this way, so we need to update kata-manager to allow it to run on a standard/non-dev environment.