Document logger.timestampPrefix config (#151)

Author: Ndpnt

content/_index.en.md

@@ -323,7 +323,8 @@ The default configuration can be found in `config/default.json`. The full refere
         "to": "The address to send the email to in case of an error",
         "from": "The address from which to send the email",
         "sendWarnings": "Boolean. Set to true to also send email in case of warning",
-      }
+      },
+      "timestampPrefix": "Boolean. Set to true to prefix the timestamp of the error message with the current date (in ISO 8601 format YYYY-MM-DDTHH:MM:SSZ); see below"
     },
     "reporter": { // Reporter mechanism to create GitHub issues when terms content is inaccessible
       "githubIssues": {
@@ -351,6 +352,10 @@ The default configuration is merged with (and overridden by) environment-specifi
 
 For development, in order to have a local configuration that overrides the existing config, it is recommended to create a `config/development.json` file.
 
+#### Logging
+
+Setting `logger.timestampPrefix` to `false` can be useful when logs are being collected by a process manager (like PM2) that already adds timestamps to log entries. This avoids duplicate timestamps in the logs.
+
 #### Schedules
 
 Schedules for tracking and dataset publication are defined using Cron expressions.