Add num_imgs and this_img as private components to `prif_team_type`

[ktras]

• [ ] Add num_imgs and this_img as private components to prif_team_type
• [ ] Change definitions of versions of this_image and num_images that do not use optional arguments to use the above components
• [ ] Add back in corresponding static global variables in caffeine.c

NOTE: All of the above are in reference to the initial state/ initial team and any identifiers should be named carefully to make this clear.