Create Approach Set term

[faridseifi]

We have Approach Information (PSDO_0000030) but we do not have an Approach Set term. We need this term to be added to the

• "Has precondition" of Approach causal pathways
• "is_about" of Approach related message templates

[zachll]

• Add motivating set class
• Remove "performance" from set terms
• Replace "gap" with "comparison" in terms and definitions
• Add streak set classes
• Move definition into new field for streak information classes