Website Builder Development including Infrastructure

Hello, I need professional developer who can create a modern website builder and provide recommendation for the infrastructure (creating subdomain and split disk space automatically), etc. Preferred if you have done similar project before for at least one year. If you are not sure, what is website builder, you can google first with keyword "website builder". If CustomerA want to create website through this system, then system will automatically create subdomain for him, such as [login to view URL] and shared resource will be automatically assigned to him. The website will provide all necessary features and template that he need, CustomerA just need to click and drag without need to do any coding. By applying this, you are agreed that you will do a simple technical test, interview and need to sign NDA about not reuse or publish or share the code or part of the code to others. Simple technical test: Please create max 5 page of high level technical specification document in how you will achieve to develop website builder (include technical architecture design how you achieve the creating of subdomain and split disk space automatically, provide template and features, etc.). Please include architecture diagram if necessary. You are free to recommend any technologies to achieve this in most effective way, such as AWS, etc.