Update documentation

[floesche]

The goal of this task is to keep the documentation up to date with the state of the setup.

As a result, the step-by-step guide might contain the following information:

• complete Micromanipulator build instruction
• instructions on how to set up FicTrac (what we learned from Functional test of FicTrac #12 and Track auto-rotation of sphere via FicTrac #15)
• instruction on how to set up and power the illumination
• previously known issues with laser-cut parts and what we learned from it
• complete camera modification steps

Document formatting (eg via paragraph styles) could help improve readability. How can we improve the figures (eg creating figures with sub-panels, different type of alignment…)? All this is up for discussion.