text: Title: Add option to disable .env load
  Body: ## Problem
  
  Currently, .env files are loaded by default and if the behaviour is desired to be disabled it is needed to be defined in every instance of `Prisma`.
  In many production systems, it is not desired to load environment variables from .env files.
  
  ## Suggested solution
  
  Add environment variable to disable the behaviour
  
  ## Alternatives
  
  Change the default to not load .env
  
  ## Additional context
  
  When loading the .env in my project `Prisma` overridden the environment variable I had already set for `DATABAE_URL` (which seems like a bug on its own) 
  