SMA Port for Modular Snap Together Raspberry Pi 2B/3B/3B+/4

Added a hole as well as a recessed nut seat for standard SMA (female/male) connectors. This allows for easy connection of antennas, Low Pass Filters (LPF), or dummy loads when experimenting with software like rpitx. As noted on the model: I highly recommend never operating the transmitter without a proper load. Use at your own risk if you choose to do so.