Use generic Terraform modules in platform modules

[invidian]

c4b4162 introduced new Terraform modules, which should be re-usable across platforms.

To avoid duplicating and getting Terraform code out of sync, we should carefully migrate existing platforms to use those new modules.

Perhaps while doing the migration we should introduce some e2e tests, which makes sure we don't introduce a regression while doing the migration.

This is part of #449