Add function to globally change SpamAssassin threshold score and auto-delete score for all accounts

As a web-hosting provider I would like to add functionality to WHM to allow greater control over SpamAssassin settings such as changing the default threshold score and auto-delete threshold score for all accounts in one step to simplify user account management.

Note: the UAPI function SpamAssassin::update_user_preference should also be updated to include a way to set the auto-delete score, as it currently only allows setting the regular "required_score" for determining if a message is spam, but doesn't allow setting the parameter to modify the auto-delete score via the API.

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Add a WHM function to allow changing the default SpamAssassin threshold score and auto-delete threshold score for all accounts in one step.

Also allow the auto-delete threshold score to be set in the UAPI function: SpamAssassin::update_user_preferenceCurrently it only seems to be able to set the required score for marking an item as spam, but not for setting the auto-delete score configuration setting.