Fix EZP-21733: Improve exceptions thrown in RoleService

This PR resolves issue https://jira.ez.no/browse/EZP-21733

`LimitationValidationException` is introduced and thrown in `RoleService` methods persisting Limitations.
`InvalidArgumentException` is documented on selected methods.

Also REST specification is updated with new error codes, `LimitationValidationException` is handled with `HTTP 400 BadRequest`.

Additional: small fixes in REST specification and XSD schema.