Create FormModal component to clean up modal code

[cory2067]

One common pattern in this repo is having a form inside a modal.

Something vaguely like this to give an idea of what I mean:

function FormModal(props) { // todo flesh out these props
  const [formData, setFormData] = useState(props.initialFormData);
  const onValuesChange = (newData) => setFormData({...formData, ...newData});
  return (
    <Modal
       ...props,
       onOk={() => props.handleOk(formData)}
    >
        <Form onValuesChange={onValuesChange} initialValues={props.initialFormData}
          { props.formContents}
       </Form>
    </Modal>
  )
}

This can help reduce some of the boilerplate involved in setting up form modals