validate: add --valid-output option

[jqnatividad]

Per the usage text:

--valid-output <file>      Change validation mode behavior so if ALL rows are valid, to pass it to
                           output, return exit code 1, and set stderr to the number of valid rows.
                           Setting this will override the default behavior of creating
                           a valid file only when there are invalid records.
                           To send valid records to stdout, use `-` as the filename.

resolves #1728

[github-advanced-security]

devskim found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.