Assembly issues: Backpack

[ameyp]

List of issues I encountered during assembly

• The backpack extrusions should be mounted using M5x8 BHCS, the eDrawing says M5x10 BHCS. The latter are too long and bottom out with a 1mm gap left between the bolt head and the back panel
• The BOM needs a lot more M5x8 BHCS. Right now it says 2, but everything in the backpack uses them