As shown in the RAK4630 IO Pins and Peripherals, there are two I2C connection available, which are P0.13, P0.14 for I2C and P0.2, P0.25 for I2C_2. However, in the example, we only have Wire, which I assume is assigned to P0.13, P0.14 I2C. How can I access the another I2C_2? Can both I2C be used at the same time? If I do not use I2C_2, can I use those 2 pins and GPIO for input/output?