qa workflow: Implement enable_regression_tracking parameter
For regression tracking (#791), the blueprint requires a new enable_regression_tracking
parameter.
The basic logic is described in Behavior with enable_regression_tracking
set to True.
This issue also includes implementing the appropriate comparison logic for each type of QA task, described in Implementation of QA results regression analysis.
Depends on #905 (closed), #906 (closed), and #907 (closed).
Edited by Colin Watson