Add grouping by report type

Summary

Per default the data that is displayed within the "Open Vulnerabilities over Time" chart is grouped by severity.

We also want to give the option to group by report type, so users can get an overview of how different report types are affected.

Implementation Plan

• Add buttons to chart component (group by severity/group by report type)
• Emit event when button is clicked
• Capture event within security dashboard and update the GraphQL query variables accordingly