Add logger for codemods

[ssutar]

• The logger will log the validation failures if any
• Will have information like path, timestamp and status which can be used for debugging

[pzuraq]

Looks good for starters. I think the output will be difficult for users to parse since it's more of a traditional server log. It would be better to have output that is markdown and readable, I think the output of the ember-modules-codemod was a great example of this, it's a markdown file that's very easy for people to read and then follow up on.