[INSTALLER] Check for required tools on the very first install and provide conditional instructions

[AlexSkrypnyk]

On a very firs install, a user sees this success message with the next steps.

It looks like that running ahoy build would build the site straight away. But this will work only if Docker, Ahoy and Pygmy are installed.

Need to add tooling check to the installer and alter the next steps section in the resulting message to tell the user that these need to be installed from a specific URL.