Add KPI: Builder Friendliness Score

[melkuo]

This tool could benefit from a KPI or a measure of sometime to quantify how bills are performing.

One idea is to measure "Builder Friendliness" over time. This could involve having the LLM evaluate an impact of each bill (currently the LLM only makes a binary positive/negative for each bill). These impacts could then be averaged over time to show this score.

It would be interested to divide this further into categories, e.g. are there certain areas where bills are becoming more/less builder-friendly?

Original suggestion here. See related ticket here