Add error handing for front matter formatting errors

[refactorsaurusrex]

Summary

It's easy to make a formatting error to the yaml front matter that goes unnoticed until all journal commands start failing due to a parsing error. I recently encountered this problem because I had manually written a readme tag as a yaml array rather than as a scalar value.

To address this situation, all cmdlets should catch all entries that cannot be correctly parsed and display a list to the user. The list should include the file path of the entry, the error, and instructions to fix.