[Stats] Add percentage columns

[AgustinSilverfin]

Description

Calculate the amount of templates that are externally managed and have unit tests Add them to new columns in the output csv file Include percentage in the overview displayed on the terminal

Type of change

• [ ] Bug fix
• [X] New feature
• [ ] Breaking change

Checklist

• [ ] README updated (if needed)
• [X] Version updated (if needed)
• [ ] Documentation updated (if needed)