Reporting: ReportService needs a method to return default template for multiple accounts

getDefaultReportTemplate returns the template for a single account, but only

takes a single account as an argument. getReportColumnsBean takes multiple

accounts but returns all possible report columns for a combination of reports.

Abhi needs a way to request the default columns when two accounts are combined.

The CCC is apparently doing this with direct database calls which would also

need to be cleaned up by making use of this new call.

Abhi has a workaround and the accounts where the problem occurred are leaving us

anyway so I am guessing this is low priority.