Rename `Packages and Registries > Infrastructure Registry` to `Packages and Registries > Terraform modules`

Summary

Based on this comment, we need to rename the Packages and Registries > Infrastructure registry to Packages and Registries > Terraform modules, and update all documentation references to be consistent.

Terraform => Terrafrom states
Infrastructure Registry => Terraform modules
Feature Flags => Feature flags

This issue focuses on Packages and Registries > Infrastructure Registry to Packages and Registries > Terraform modules

Improvements

Risks

Involved components

Optional: Intended side effects

Optional: Missing test coverage