Update MCU_Module.kicad_sym

This is my first contribution, I try to fellow the KLC. This is a symbol for the CMOD A7 from Digilent. I use the Arduino Mini as a reference.

The datasheet can be found there : https://reference.digilentinc.com/reference/programmable-logic/cmod-a7/reference-manual https://github.com/Digilent/digilent-xdc/blob/master/Cmod-A7-Master.xdc https://reference.digilentinc.com/_media/reference/programmable-logic/cmod-a7/cmod_a7_sch.pdf

Screenshot symbol :

The footprint will be send in an other merge request.