Fix typing and provide reasonable defaults for existing component's props

[jakobz]

Certain components already have reasonable defaults for some props, but our typing requires these props:

NotificationCard - onClose, onSuccess, color (can be defaulted to blue). Revisit if we really need 'id' and 'key' - I believe they are internally generated in the NotificationContext. NumericInput - min, max DatePicker - format IconContainer - onClick

Let's:

• fix typings ( { prop: X } => { prop?: X | null }
• remove unnecessary props from our demos and examples