Fixing image issues with operator user and adding/updating some packages

• Removing the user if it already exists, to assign the right uid/gid. This is relevant when creating the operator user
• Fix issue copying /home/conda/.cache directory, sometimes there are issues with permissions that has to be ignored.
• Updates:
  • ess_nexus to 0.9.7
  • Open XAL to 6.6
  • Open XAL lattice to 2.4
• New Python packages:
  • pre-commit
  • flake8