Support more than a single analog Mux

[ingobecker]

Currently only a single analog multiplexer can be addressed. In order to use more than a single multiplexer proper addressing of the multiplexer inhibition lines needs to be supported.

• connect a second analog multiplexer to the shift register with at least one input
• implement inhibition line addressing in the Stm32Backend
• setup a poc with <max_analog_mux_inputs> + 1 Input s to test more than a single analog multiplexer