Support additional schema attributes

[mficzel]

OpenApi Schemas have some properties we cannot deduct properly (yet). We should find a way to support them by deducting as much as possible from as little code as possible.

all: example
array: uniqueItems, minItems, maxItems
string: pattern, format, minLength, maxLength
integer: multipleOf
number: minimum, maximum, exclusiveMinimum, exclusiveMaximum
object: additionalProperties (das wäre unstructured json)

see: https://swagger.io/docs/specification/data-models/data-types/