ci: adding GitHub Actions pipeline for Terraform, Ansible, and shell lint

[TrishaG189]

Summary

Introduces a multi-job CI pipeline that runs automatically on every push and pull request targeting main. This ensures infrastructure code quality and security posture are validated before any merge.

What this adds

• Terraform fmt + validate — catches formatting drift and syntax errors early
• tflint — Terraform best-practice linting (unused vars, deprecated syntax, provider rules)
• Checkov — static security analysis of Terraform configs (IAM policies, open security groups, unencrypted storage, etc.)
• ansible-lint — enforces Ansible best practices across all playbooks
• shellcheck — lints deployment shell scripts for common bugs and portability issues
• Security gate job — a final aggregation job that only passes when all prior jobs succeed; this makes it easy to set as a required status check on branch protection rules

Why this matters

Right now there is no automated quality gate on the repository. As the honeynet scales to multi-region and multi-cloud, a single misconfigured security group or IAM role could expose the honeynet management plane. This pipeline catches those issues in code review before they reach cloud infrastructure.
(Note: Pipeline was made fault-tolerant to gracefully skip checks for directories that do not exist yet).
#9