ESP32 Miner v3.1

I wanted to stack the boards using arudino sized standoffs.

I wanted a screw terminal for power to power the 6 ESPs.

I wanted to use headers for the ESP so that if the ESPs fail i can replace them easily.

My v1 design was learning the tools and discarded.

My v2 design didn't have headers, i was going to solder the ESP32 to the board, then reazlied this was pretty inflexible.

My v3 design added headers and improved layout.

Note while the ESP32 are in the design schematic thats just so i can easily transfer the silk layer from that design.

My v3.1 design replaced power connector with shorted connector as in stacked config the pins of the screw power connector on the top board touched the screws in the terminal on the next board down. Also increased the gap between top row of ESPs and bottom row to account for minor differences in pin placement on different ESPs (basically the two rows overlapped by 1.5mm in the 3.0 design).