Add temporary group count column and apply scaler on 12 TPC-H aggregates

[mIXs222]

Changes:

• Add group count to the preceding aggregate node for estimating group cardinality.
• Apply to 9 SUM/COUNT queries and 3 AVG queries.

Queries that are improved over no-scale (linear error):

• q1
• q4
• q5
• q6
• q7
• q9
• q12
• q17
• q19

3 Queries that remain the same (converging error):

• q8
• q14
• q22