Extend Nest API with OWASP Board of directors (members and candidates)

**Describe the solution you'd like**
We have `BoardOfDirectors` model. We can extend the REST API with the boards data and filter it by year.

**Are you going to work on implementing this?**

- [x] Yes
- [ ] No

**Additional context**
Add any other context or screenshots about the feature request here.

Locate the BoardOfDirectors model and the existing REST API entry points for related board data. Check how members and candidates are represented, then add board data with filtering by year; done means the API exposes both datasets and returns the requested year's results.

Written by the indexing model from the issue text.