Add the "fake" reliability metric to have example of Business Rule

The proposal is to use a simple Engagement Factor as a reliability metric:

How to calculate de metric:

Variables:
- Active Engagement Multiplier - AEM
- Closed Issues (last month) - CI
- Opened Issues (last month)- OI
- Merged Pull Requests (last month) - MPR
- Proposed Pull Requests (last month) - PPR

Formula: (OI + PPR + (CI * AEM) + (MPR * AEM)) / 100 
