WL-3642 : wrong subject line for help request

This change is to use a different subject line in the email if they click on 'Ask for Help' vs 'Technical Problem' (they use the same handlebars template and url)

I've made a new entitybroker url  for 'Ask for Help' (like the others) and I feed a 'HELPDESK' constant through to tell if they clicked on 'Ask for Help' rather than 'Technical Problem'.  This means that the enum column type of sakai_feedback.report_type needs to be extended also.  (There is also a script attached to the JIRA to alter the column data type).