Update instructions to take advantage of GitBuilding v0.11

Merge once:

• Made use of the info links and info/warning/caution boxes
• Deduplicated the instructions for the upright microscope
• Built all STLs the upright microscope needs
• Customise how instructions render (OpenFlexure branding)
• Add Julian to author list in instructions
• Added renders for the low-cost optics
• GitBuilding v0.11 is released