Add Zod's built-in string transformations as field attributes

[simonedelmann]

As discussed in Discord:

Zod has built-in string transformations .trim() / .toUpperCase() / .toLowerCase()

This PR adds data validation attributes @trim / @upper / @lower to ZModel:

model User {
    // ...
    name String @length(min: 1) @trim
    slug String @lower
    heroText String @upper
}

[ymc9]

Thank you for working on it @simonedelmann ! I'm merging it to dev and will include it in the next release (around 2/15). I'll also check if more changes are needed to make it effective for Prisma create/update operations.