Add fail_on_output_error CLI option for sink failures (#672)

* Add fail-on-output-error option and CLI regression test

* Broaden fail_on_output_error coverage for disabled and multi-sink paths

docs/source/usage.md

@@ -146,6 +146,9 @@ The full set of configuration options are:
   - `dns_timeout` - float: DNS timeout period
   - `debug` - bool: Print debugging messages
   - `silent` - bool: Only print errors (Default: `True`)
+  - `fail_on_output_error` - bool: Exit with a non-zero status code if
+      any configured output destination fails while saving/publishing
+      reports (Default: `False`)
   - `log_file` - str: Write log messages to a file at this path
   - `n_procs` - int: Number of process to run in parallel when
       parsing in CLI mode (Default: `1`)