* Use window functions for SQL drivers for cumulative count and sum

* H2/Snowflake/Redshift implementation

* Test fixes 

* Use SELECT expression positions as the default window function implementation

* Some test fixes.

* Fix bugs in add-alias-info

* MongoDB fixes

* Another pass

* BigQuery should use positions?

* BigQuery almost works 100% now.

* MLv2 fix conversion behavior for expressions with type info

* Add transformations for nesting cumulative aggregations in expressions

* Minor tweaks

* MLv2 should escape aliases using driver/escape-alias (dynamically bind this)

* Kondo fix

* Lint fixes 

* More test fixes and revert test changes

* Update some tests to use correct case for nominal Field literal refs

* Wow! BigQuery is fixed! Remove upgrade-field-literals middleware

* Disable tests for the failing drivers, we can fix in follow-on PRs.

* Enable BigQuery :window-functions

* Extra info

* Add GH issue numbers

* Update more GH issue numbers

* Fix SQL Server!!!! wooo

* I THOUGHT WE WERE DISABLING SPARK SQL!!!!!!!!!!1

* Cleanup to get things ready for review.

* Snowflake + Vertica shouldn't use output column numbers for ORDER BY in OVER

* Code cleanup

* Snowflake + Vertica shouldn't use output column numbers for ORDER BY in OVER

* Code cleanup

* Test fixes 

* Much simpler BigQuery implementation

* Add GH issue context

* Remove commented-out code

* Remove unused add-stage-at-index

* Documentation

* Test fix? 

* Test fix