Is your feature request related to a problem? Please describe.
kics is not Terraform-specific - it supports other IaC manifests like Ansible, Kubernetes, Pulumi and more. I don't see a reason to limit it, by default, only to .tf files. Right now I am running it in repos containing Ansible code and I just used TERRAFORM_KICS_FILE_EXTENSIONS: ["*"], but this doesn't look nice.

Describe the solution you'd like
kics should be added to REPOSITORY and TERRAFORM_KICS should be removed in megalinter 7.0

Describe alternatives you've considered
Same thing as with TERRAFORM_CHECKOV