Update output report format

[byrnereese]

I am wanting to build a github action around this module. It would be awesome if the script could output a summary. This summary could then be used to create a ticket inside of a github repository. Attached is a screenshot from markdown-link-check which has a good summary format.

I would also add that issue #10 relating to the output of socket errors also makes the reports a little harder to read and thus harder for engineers to address in an issue that one might create as a result of a failure.