docs: Create a Contribution Guide for OpenAEV

[maximerafaillac]

Use case

OpenAEV is still in its early stages, and the community is growing. Without clear contribution guidelines, potential contributors may feel lost or hesitant to participate — which risks slowing down community adoption and increasing the maintenance burden on the core team.

Current Workaround

There is currently no contribution guide. Contributors must infer the expected workflow (branching, PR format, code style, etc.) by looking at existing code and PRs, which is time-consuming and inconsistent.

Proposed Solution

Create a CONTRIBUTING.md guide (and/or a dedicated docs section) that covers at minimum:

• How to set up the development environment
• How to submit a bug report or feature request
• How to open a Pull Request (branch naming, PR description, review process)
• Code style and conventions
• Collector-specific guidelines (structure, naming, testing)

The guide should be modeled after the OpenCTI contribution guide — clear, welcoming, and structured for both first-time and experienced contributors.

Additional Information

This is a foundational step to:

• Secure the project's long-term sustainability
• Lower the barrier to entry for community contributors
• Establish standards early

Would you be willing to submit a PR?

@maximerafaillac is available to help draft the initial version once the OpenCTI guide link is confirmed.