Onboard JOB benchmark

[kyukhin]

There's pretty interesting paper [1] which among other things introduces
SELECT-oriented benchmark w/ IMBD-based dataset [2].

Let's onboard it.

[1] - https://github.com/gregrahn/join-order-benchmark
[2] - http://www.vldb.org/pvldb/vol9/p204-leis.pdf

[opomuc]

I have a snapshot of this dataset.