Add Errors.toLogFormat

Allows errors to be formatted and sanitized for logging. Removes sensitive paths
such as the app root directory.

Ideally, this module would be called singular `Error` but that is already a
global name. Using `Errors` plural is  similar to Java convention for utilities
such as `Arrays`, `Collections`, `Files`, etc. See:
https://stackoverflow.com/a/11673838

js/modules/types/errors.js

@@ -0,0 +1,17 @@
+/* eslint-env node */
+
+const Path = require('path');
+
+const toError = require('ensure-error');
+
+
+const APP_ROOT_PATH = Path.join(__dirname, '..', '..', '..');
+const APP_ROOT_PATH_PATTERN = new RegExp(APP_ROOT_PATH, 'g');
+
+//      toLogFormat :: Error -> String
+exports.toLogFormat = (error) => {
+  const normalizedError = toError(error);
+  const stackWithoutPrivatePaths =
+    normalizedError.stack.replace(APP_ROOT_PATH_PATTERN, '<REDACTED_PATH>');
+  return stackWithoutPrivatePaths;
+};