Feat: Add PDB file screenshot with coloring according to B-factors to output and in the report

[berntpopp]

Description:
Add a feature to generate a screenshot of the PDB file with coloring based on B-factors. This screenshot should be included in the output directory and referenced in the final report to provide a visual representation of the protein structure with relevant B-factor data.

Expected Behavior:

• Generate an image of the PDB structure with B-factor coloring.
• Save this image in the output directory.
• Include this image in the final report generated by the pipeline.

Proposed Solution:

• Use an appropriate molecular visualization tool (e.g., PyMOL or ChimeraX) to generate the colored PDB structure image.
• Integrate the screenshot generation step into the pipeline.

[berntpopp]

related to #44