PARTS: Control Unit Case: As a user, I want an access panel for the SD card

[sparklestheunicorn]

Cause I don't want to have to remove the R Pi to swap it out.

[phaseloop]

As we plan to go with "nanolab" USB route, this probably should go as one of the requirement for standalone Controller design. Unless we plan to use any of the million existing Raspberry case designs because there would essentially be no difference between Controller talking over USB to "nanolab" and any regular Raspberry in a case.