Idea: Provision git first

[tomjn]

We should investigate if we can provision the cloning of utilities before the main provisioner. This way rather than duplicating the PHP provisioner, we can launch it from the main provisioner. Likewise we can rely more on utility code and we could clone site templates earlier, then run the provisioners later

[tomjn]

I believe this should be done by splitting the main provisioner into 2 steps, so that the first step can install git and the second step can run at the same time sites/utilities are cloned #2270