refactor(misconf): Merging trivy-iac into Trivy

[simar7]

After several discussions it was concluded that it might be best to merge trivy-iac into Trivy. This has several benefits:

1. trivy-iac release can be coupled with Trivy. This will reduce co-ordination between the two projects, previously defsec (now trivy-iac) will have to release first, and then be incorporated into Trivy.
2. Easier contribution workflow: New services added to misconfiguration scanning can be directly added to Trivy as misconfiguration scanning is a core component of Trivy.

This transition will follow the fanal model. We plan to integrate trivy-iac into Trivy in a similar fashion.

As for trivy-policies it will remain as-is but will be renamed trivy-checks more on that in this issue: #5609

As for trivy-aws, it will remain as-is for now. In the future, it will be converted into a Trivy plugin, thereby eliminating and AWS SDK dependencies from within Trivy, thereby reducing the overall dependency footprint of Trivy.