Is Storefront (Salesforce Commerce Cloud) made out of Visualforce page? Or we can use Web Technologies (Node, Angular, Bootstrap etc) to build the Storefront?
Related to Salesforce B2C Commerce (pka Demandware):
You can use Angular, Bootstrap, etc. client-side frameworks.
Salesforce B2C Commerce is on different technology stack from the rest of the Salesforce core platform products, so visualforce is not applicable technology.
As for Salesforce B2B Commerce (pka CloudCraze): It is build on top of the core platform so it uses the same technology stack, so visualforce may be applicable depending on your usage scenario.
Check if https://trailhead.salesforce.com/en/academy/classes/b2b201-b2b-commerce-technical-training/ course may be helpful for you.