add rigor rubrics and unittests

[HamedBabaei]

Relevant Issue: #33
Relevant PRs: #41

Changes:

• Prompts – Integrated pairwise prompt templates for the deep research dimension: Rigor that includes the rubric EpistemicCalibration, QuantitativeEvidenceAndUncertainty, and ExplicitUncertainty.
• Introduced NLP & Ecology-specific pairwise examples for each rubric.
• Documentation – Added the pairwise evaluation information for the dimension - Rigor.
• Unit test for injectors