Automate Aggregation of Overall Coverage per project

[DonggeLiu]

Context:
Project-level coverage increment is crucial for accurately reporting overall progress and reflecting the true extent of the code tested. Currently, our experiment reports only display coverage increments per individual fuzz target. Users must manually execute report/aggregate_coverage_diff.py to calculate total project improvements. Each project has 5 functions under test, with 10 fuzz targets per function.

Goal:
Automate the execution of aggregate_coverage_diff.py for each project in an experiment and include the overall coverage improvement in the HTML report.