As far as I am aware, that is not possible at the moment! What I have done is created a template with best practises, and UI elements and given other PowerApps devs in my org "Owner" access to it. On the first screen of the template, I am advising them to immediately go to "Save As" to save the template as their own new app.
I had the same issue, fortunaly most peoples first app is not going to be a mission critical app. They're likely to just be learning.
I suggest looking at Flow for the answer and user the PowerApps Admin connectors to help. So Create a flow that looks at all the powerapps in your tenant and store those in a list, then send out an introductory email to any and all new powerapps makers with the template on or better still links to the file somewhere on your estate, also links to training and your companies governance policy etc. It might also be a good idea to review their trainging on GDPR just to be on the safe side.
Track their useage and as they get more apps ofefer them more training and then make them a champion!