Use tempTable class in creation of dedupe table.

Use tempTable class in creation of dedupe table.

The is covered by unit tests ContactTest::testDuplicateTest and DedupeFinderTest::testUnsupervisedDupes

There are some others in this file but I focussed on keeping the scope to a single table replacement.

A couple of thoughts
1) I passed the indexes in as 'columns' - works, is tested so we'd know if anything broke it but it feels a bit ug
2) I think it makes sense to add a descontruct on the class to drop the temp tables
3) the longer syntax for referring to the table is a bit wordy - but harmless I guess & reformatting would
help