Add a new function to aggregate user stats among projects

[udaynwa]

Description

1. This function should take the existing users stats for all projects
2. Aggregate per user stats per user id
3. We should be able to consider additional information here as well

[udaynwa]

To-do

• @udaynwa to follow up with @k9845 in the progress.
• Discuss with Dan and team about the new data structure and it's impact on existing functions

[k9845]

Let's mention what fields are to be included in the export. @udaynwa @frozenhelium