O3 autofocus improvement

[ieivanov]

This PR contains the following improvements to the shrimPy acquisition engine:

• more robust O3 autofocus
  • re-running O3 autofocus with extended range if it is out of range on the first try
  • removing the O3 travel limits to account for both O2 and O3 drifting together
  • backlash correction of the O3 piezo for more consistent refocusing
  • ability to skip O3 refocus in given wells, e.g. if they don't contain fluorescent markers
  • increased focus finder threshold to safeguard against false peaks
  • updating laser powers immediately after autoexposure rather than in hook functions to prevent O3 refocus running with incorrect illumination settings
• turning off Live mode if it is running
• checking if the illumination.csv file is present during setup when manual autoexposure is enabled
• moving scripts folder to top level

This PR is tested and ready to merge.