From googling to triage COMPASS-3727

1. Show detailed error message of why my JSON is invalid.

https://www.npmjs.com/package/jsonlint provides output like:

Error: Parse error on line 1:
...esentiustoodio.us"}{"_id":{"$oid":"5864
----------------------^
Expecting 'EOF', '}', ',', ']', got '{'

2. Handle invalid dirty JSON automatically.

Needs more googling (search for dirty || loose JSON parsing) but have used npm modules in the past that can handle typos like the above without the user needing to fix and try again.