PCB changes for DIB/BB3 compatibility

[fietser28]

• [x] This is a DIB module size
• [x] the main communication connector is in place
• [x] the EEPROM is placed on analog PCB
• [x] there is a connector routing the SPI and power connections to a (to be designed) piggy board
• [x] screw holes for panel are in place
• [ ] the DIB power channel connector for parallel /serial operation is not implemented and wouldn't fit: one of the banana sockets is in the way and there is not much place left to shift everything over. It is also not clear if this would be useful to have.

[fietser28]

Also see eez-open/modular-psu#120