Optics clean up

There is so much legacy code in the optics section that it is very hard to add new features or adjust anything. I think we need to:

• Remove really old unbuilt optics module styles
• Move any low-cost optics we still support to the lens spacer/platform mount style
• Decide what cameras we do still support (Logitech C270 does not fit in V6)
• Make all optical trains (from lens to camera) be set by calculated spacings. Currently camera is set from the bottom of the microscope and lens from the sample. This causes the optical train to change as the sample_z parameter is changed. This is unintuitive and causes things to break.
• Decide whether and how to support 35mm parfocal

/cc @rwb27 @jtc42