Add tutorials

Added by Johan Henning about 1 year ago

It would be nice to add tutorials for the Zynq-7000 to the Waijung 2 User Guide (as was done for the ESP32). This makes the learning curve less steep.
For the adc_demo for example the explanation is very brief (Connect voltage sources to AUX7 and AUX14).
A schematic and a picture could help a lot. I used a potmeter of 500 ohm and a resistor of 1k2 in the +3V3 line to create a voltage between 0 and 0.97V. This is how it looks like: