Oresat CFC Mini-Backplane

This is the backplane for UMBC's Air Harp 2 sensor, which is going to include a PIRT SWIR sensor using OreSat's CFC system.

Requirements:

Match the DXF outline from Joe, including placement of connectors and the fastener holes.
- Probably remove solder mask from both sides of those fastener holes just in case.
- Probably put the external connectors in the upper right hand corner.
Use an OreSat 20 pin debug connector on this backplane so we can run USB from the CFC processor to the external connector using the CFC processor's debug connector.
External connections
- Power should come through a 0.2 inch euroterminal for two 20 AWG wires.
- USB should be via a Harwin M80-5400442 connector. Pin-out is determined by us.
  - signals: USB D+, USB D-, Vbus, and GND.
  - Vbus should go through a 10k ohm resistor between the 20 pin debug connector and the Harwin connector.

Easiest thing to do:

Both OPDs should come on by default, so we need to bypass or hack the OPDs to turn on.
We may want to figure out some way to power the local OPDs so they're not doing anything weird with their connections to the Octavo.

A Ben Idea:

Add a 8.4V to 5V LDO, a Trinket M0, two 4.7K resistors, and use Oliver Rew's Arduino code to turn on both CFC cards
This assumes we have Trinkets, which I believe we have a bunch lying around.
This is cute because we don't have to modify the sensor or processor card, which I hate doing.
Be careful of the 8.4V max input voltage can power the trinket without frying it (thus the 5V LDO).