fix registry urls on generate missing images list and adds registry info to digests

[tashima42]

Problem: The --registry flag wasn't working because the registry URL was hardcoded in a function
Solution: Use the registry info to get the correct registry information

Other updates:

• Adds the registry information to docker digests
• Adds the verbose flag --verbose, -V
• Adds the ecm log package which only prints info to sdout if verbose is enabled.