Implement the package dependency graph

[git-afsantos]

• It might be useful to take Computation Graph component as a basis, and use a D3 force graph to display packages and their dependencies.
• Packages can be color-coded according to the number of reported issues. For example, HAROS1 had a few heuristics to choose an appropriate color, based on the average number of issues per line of code. We can reuse that, or come up with something better.
• We can also look into other examples on the D3 documentation pages for inspiration. Maybe there are other views that make more sense than a force-directed graph.
• A feature that was commonly requested for HAROS (but never got implemented) was to also display third-party package dependencies. HAROS built a graph using only the packages that you provided for analysis. External packages should be displayed differently (even if it is just a different color).