Adapt a more conflict resistant naming for Prisma client's types

[pantharshit00]

Right now properties like ${name}Client are ending up in the denyList and it is very common to name something like UserClient.

This adds unnecessary friction and we can totally avoid this by using a more conflict resistant naming for types like User__Client.

Internal: https://prisma-company.slack.com/archives/CUXLS0Z6K/p1590736839231000

Related: prisma/prisma#2539

[dodas]

What about generating those classes conflicting with model names to different file and import them to index under different, perhaps very conflict-tolerant/avoiding names?

[pantharshit00]

Yes, that can be one way of doing that.

[janpio]

Possibly related: prisma/prisma#2656

[timsuchanek]

We now implemented Prisma__UserClient.