Add option to generate textarea for Strings

[madeleineostoja]

Would be great to have a configuration option to generate textareas rather than text inputs for Strings in the schema, for dealing with larger chunks of data.

As soon as you get a value larger than a few words text inputs become unweildy for the user to work with, and IMO textareas for Strings is a better default regardless. But adding a non-breaking config option would at least solve that (I imagine common) use-case.