feat(react-kit): accept defaultProps in withrx selector result

[raveclassic]

This allows to pass handlers along with props in WithRXSelector

BREAKING CHANGES:

• defaultProps argument is moved to WithRXSelectorResult;
• static defaultProps property is removed;
• props$ stream passed to selector doesn't contain fields from defaultProps anymore
• withRX now accepts Target separately for better type inference in props/defaultProps

[sutarmin]

Cool. Now we have correct type inference and autocomplete in defaultProps, and also no longer needed to wrap callbacks into Observables to return them from withRX, we can just pass callbacks through defaultProps.