* Adds Druid SQL query examples for the Timeseries and GroupBy Native queries in the stats aggregator docs page
* Updates intervals in Native Query to remove excess Time part in timestamp
* Moves Druid SQL section above Native query because sql used more often by users
* removes old Druid SQL sections
* Adds TopN Druid SQL query using ORDER BY and LIMIT
* Adds table for Druid SQL variance and standard deviation functions
* Update docs/development/extensions-core/stats.md
Co-authored-by: Abhishek Radhakrishnan <abhishek.rb19@gmail.com>
---------
Co-authored-by: Karan Kumar <karankumar1100@gmail.com>
Co-authored-by: Abhishek Radhakrishnan <abhishek.rb19@gmail.com>