feat: add ContributorStats model for tracking contributor activity

[JisanAR03]

Pros of the ContributorStats Model Compared to the Previous Approach:

1. Improved Query Performance:

   • Aggregated data eliminates the need to process individual event-level rows for each query, significantly speeding up statistics calculations.

2. Optimized Storage:

   • Storing daily stats for the last 30 days and monthly stats for older data reduces the database size compared to storing all individual events.

3. Simplified Data Retrieval:

   • Directly querying daily or monthly aggregated rows simplifies frontend logic for displaying contributor activity over different time periods (e.g., 7 days, 30 days, yearly).

4. Efficient Historical Management:

   • Rolling up old daily stats into monthly data ensures historical trends are preserved without keeping unnecessary day-level details.

5. Customizable Granularity:

   • The granularity field allows flexible storage for both daily and monthly data in a single table, making it easier to scale or adjust the data retention policy in the future.

6. Reduced API Dependency:

   • By storing aggregated stats, we avoid frequent or heavy API calls to GitHub for historical data, relying instead on pre-synced local data.

7. Scalable Design:

   • The model supports efficient handling of large contributor bases and active repositories without the database performance issues of event-level storage.

   @DonnieBLT sir, can you please review this PR ?
   another step for fix create a csv to add all owasp projects to /projects #2972