Add configuration for s3 max connections

Change default s3 msx connections to 500 and make it configurable
Allow Verifier to specify the jdbc driver for control and test
Expose queryId in PrestoResultSet
Improve support for numeric fields in json extract

Allow numeric fields without quoting in path expressions
Numeric fields match both array elements and object fields
Add 0.75 release notes
Fix style error
Document MAX_BY and update 0.75 release notes
Remove unnecessary .gitignore