Add the Terraform README to the UI

Context

From the documentation, terraform module registry can be accessed at the group & project level.

Page	Current
List
Details

Steps to reproduce

# stub file upload
def fixture_file_upload(*args, **kwargs)
  Rack::Test::UploadedFile.new(*args, **kwargs)
end

# create a terraform module package
pkg = FactoryBot.create(:terraform_module_package, project: Project.last)

Proposal

Implement the necessary adjustments in the details page UI to appropriately display the contents of the documentation. Integrate the Terraform README into the respons... (#438059 - closed) implements API to return contents of README file. Looking into how the terraform registry displays it, it seems some work is needed.