Add support for readOnly and writeOnly fields

[elsmr]

Handle readOnly and writeOnly fields in JSONSchema.

• Exclude readOnly fields from Input types.
• Exclude writeOnly fields from normal non-Input types.

https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.9.4

Other tools such as Redoc do something similar:

• filter out readOnly fields in request bodies
• filter out writeOnly fields in responses