Use support email in the 'closing' text of the system email message

[PaulBoon]

Overview of the Feature Request
Emails sent by the system contain a 'closing' text that states You may contact us for support at followed by the system email.
However there is an optional JVM setting; dataverse.mail.support-email which can be different from the system email. Using that allows you to prevent problems when the system email is not used for handling support questions.

What kind of user is the feature intended for?
Sysadmins can configure this and all users will get their system emails with improved closing text.

What inspired the request?
We have our system email set as noreply@datastations.nl; clearly not intended for asking support, but now it is used in those emails as suggestion to sent support requests.

What existing behavior do you want changed?
Instead of always using the system email it should use the support email when it is specified by the JVM option.
The existence of the JVM option and the wording in the code; BrandingUtil.getSupportTeamEmailAddress, suggest that using a support email address was intended at some point.

Any open or closed issues related to this feature request?
The installer now can not set the dataverse.mail.support-email option:
#9962