Refactor queries_grouped_by_hash and add 4 additional Optimization Scripts

[afleisc]

Some customers have a greater focus on duration of queries rather than total slots. The queries_grouped_by_hash_project/org_duration scripts break each query down by duration percentile rather than focusing solely on slot time which can save time rather than modifying a previous script.

Added two additional scripts to gain insights into customers who use BI Engine. One focuses on the duration of each BI Engine mode so they can monitor whether or not BI Engine is helping. The other focuses on why BI Engine was disabled so they can understand why BI Engine may not have been used.

Refactored queries_grouped_by_hash to add ordering and limit clauses. The current comments in the scripts don't align with the script logic.

Also updated the README to reflect some of the latest changes to queries_grouped_by_hash. There were broken links because we broke queries_grouped_by_hash into two separate scripts for project and organization.