Render schema validation errors

[Fer0x]

This is copy of internal issue created before autoviews was migrated to external github project

For discussion:
If onError callback blocks render then no need to fix different handlers for unmatched schema.

Right now we are ignoring error without onError handler.
We still can make use of this callback, but we also can make some run-time decisions when we know that that AutoView in so called "error" state.
In order to do this, we need couple of things

1. Save error in validate method https://github.com/wix-incubator/autoviews/blob/master/packages/core/src/auto-view/auto-view.tsx#L170-L172

if (!isValid && validate.errors!.length) {
    this.error = formatValidationError(validate.errors![0]);
    if (onError) {
        onError(error)
    }
}

2. propagate error to child AutoViews https://github.com/wix-incubator/autoviews/blob/master/packages/core/src/auto-view/auto-view.tsx#L154-L160

return (
    <AutoViewLogic  
        {...this.props}
        error={this.error}
        schema={subSchema!}
        validation={false}  
    />
);

3. Create error component in repository

const repo = new ComponentsRepo();

repo.registerError({
    name: 'error-component',
    predicate: props => {
        return props.error.schemaPointer === props.schemaPointer
    },
    component: props => (
         <>
              <h2
                   children={props.data.message}
              />
              <pre
                    style={{backgroundColor: red}}
                    children={JSON.stringify(props.error.data)}
              />
        </>
    )
})

4. call error component before any logic https://github.com/wix-incubator/autoviews/blob/master/packages/core/src/auto-view/auto-view.tsx#L85

const error = this.error || this.props.error;
if (error) {
     const ErrorComponent = components.getErrorComponen(this.props);
     if (ErrorComponent) {
          return <ErrorComponent {...this.props} error={error}/>
     }
}

(this will probably require to move validation to constructor and also more complex logic for wrappers)