5.0.0

Migrate terraform code to 0.12 syntax (#15)

* Migrate terraform code to 0.12 syntax

As per https://github.com/skyscrapers/engineering/issues/252

I've also switched to using alb resources directly, without an intermediate module.

This introduces breaking changes that will require a major version bump in the new release

* Switch dynamodb table to PAY_PER_REQUEST per skyscrapers/engineering#223

 (#14)

* Fix submodule path

* Update documentation and add upgrade path

* Adjust some names to avoid unnecessary replacement

* Rework tags and tag everything

* Fix lifecycle of target groups

* Update tf code in examples

* Update test dependencies

* Update go version in tests task

* Update test deps again

* Install gcc dependency in test task

* Fix edge case with null values

- nulls are not yet supported in the teleport-bootstrap-script module

* Create a fake dependency on the dynamodb tables

Otherwise the destroy process doesn't go smooth

* Fix staging acme server version

* Clean up vault version in test ci task

* Fix acme server url on globaltable test as well

#facepalm