Option to not send welcome emails to created users

I notice that there's a defined constant that is never used - CONTENT_PROFILE_CREATE_USER_SEND_EMAIL

I assume this was intended from the start to limit whether a welcome email is sent or not when a user is created so I'll use this in my patch. I'll mark this as a feature request.

In my current use case, we're using Feeds to migrate user accounts from an old system we're deprecating to Drupal and we're storing most of the users' data as Content Profile nodes in Drupal. We'd like to bulk generate Drupal user accounts from this information, but for various reasons don't want to email every single user in the list about their newly created accounts.

The main reason being that the accounts are of various ages, some as much as 5 years old, and we don't want to "spam" the whole list first during dev, then testing, then once more when we go to production. Even after we're in production, we'll have to do a fair bit of re-training over a period of time for the new users and want to walk them through the process with their pre-created new accounts rather than confuse them with an unsolicited email right off the bat.

Once we have done the initial bulk generation, we'll want to then go back to automatically sending welcome emails for new nodes that are generated through the feed importer and then converted individually, so I'd prefer to turn this into a setting rather than just hack the mailing function directly.