CI:Add Automated Result Set Validation

[mrzzy]

Motivation

Currently, the CI only runs the exercise SQL against the Sakila Database:

• This only ensures that the SQL successfully executes, but not if the SQL produces the correct result set.
• Need for correctness validation so that users can ensure the queries they executed are correct.

Requirements

• Able to collect the result set for each SQL exercise query.
• Perform data validation on the result query against expected result.
• Data validation should be handle variations in row order, column names etc.

Proposal

• Add test/%.sql Project Makefile target to test an Exercise SQL:
  • captures the result set of running the SQL query as CSV.
  • uses Great Expectations to validate the result.
• Add test-exercises job to CI to automate SQL query testing.