Add knapsack qa report and use it to run tests in parallel
Use the RSpec runner with knapsack
The way the Knapsack runner uses exec to start rspec seems
incompatible with the way we expect it to work. Plus, it requires
specifying KNAPSACK_TEST_DIR.
Instead, we use knapsacks AllocatorBuilder to select the spec
files to run, and then start rspec as normal, via
RSpec::Core::Runner.run
This also means we can incorporate tags.
Let the job run automatically
Include KNAPSACK_TEST_FILE_PATTERN in vars
Check all defined knapsack env vars before requiring knapsack