Refactor render_scorecard_summary take advantage of performance improvements of summarize_package_results

[barrettk]

render_scorecard_summary currently relies on build_risk_summary to build the risk summary dataframe.

The exported function summarize_package_results, used to rely on build_risk_summary as well, but was refactored to have significant performance improvements. render_scorecard_summary currently does not take advantage of these improvements. This is somewhat of a necessity when mapping over 1000 packages.

It's currently unclear if we will ditch build_risk_summary altogether, or just make it run summarize_package_results under the hood, and perform some additional operations to get it in the form render_scorecard_summary requires.