New Visualization: Cohort Analysis

[cdolfi]

Please describe the background and context for this new visualization
https://rwright.fedorapeople.org/reports/notebooks/CohortAnalysis.html

Describe the perspective you'd like the final visual to give
Take inspiration from the fedora graph but develop the concept to fit the 8knot usecase and data structure

Acceptance criteria for the issue and visualization to be complete

• Take the concept -> high level overview of what the visualization will be and detail it in the issue
• Review current set of queries to see if one already gathers the information needed or a small edit could get it there
• Create visualization notebook in the CHAOSS DS WG ISSUE
• Visualization notebook -> 8Knot PR for visualization following the visualization template
• Create 8Knot visualization PR from the notebook using the visualization template
• Optional - add new query using the query template

Additional context
Add any other context or screenshots about the feature request here.