There are no existing solutions on the market (which we are aware of) which would have "USB to 4 pin" power cable included (since it is unique solution).
Nonetheless, you can buy desired capacity power bank and modify its cable yourself (so that one cable's end would be USB, and another one with 4 pin connector, so that you could connect it to your RUT240). Just take note that RUT240 required 9-30 VDC voltage. Therefore, using simplest 5 V power bank would not be enough. You would need power bank with voltage higher than 9 V (but lower than 30 V).