Several classes have a "selectFields()" static method to tell callers
which fields to select from the database. With the recent comment table
change and the upcoming actor table change, this pattern has become too
simplistic as a SELECT will need to join several tables to be able to
retrieve all the needed fields.
Thus, we deprecate the selectFields() methods in favor of getQueryInfo()
methods that return tables and join conditions in addition to the
fields.
Change-Id: Idcfd15568489d9f03a7ba4460e96610d33bc4089
