Update screenshot, add Deploy Token Custom Username section

The pngquant tool was used https://pngquant.org, and particularly, the
following command:

        /usr/bin/pngquant -f --skip-if-larger --ext .png --speed 1 image.png

Before: 47584K
After : 34924K

- Remove extra method for authorize_admin_project
- Ensure project presence
- Rename 'read_repo' to 'read_repository' to be more verbose