terraform refactor: use one variables.tf for ALL venues, component version info should only be in one place

[philipjyoon]

Checked for duplicates

Yes - I've already checked

Alternatives considered

Yes - and alternatives don't suffice

Related problems

No response

Describe the feature request

variables.tf
Currently there are at least two variables.tf being used in different deployment scenarios. e2e variables.tf is used in e2e testing and int/pst/ops/etc. modules/common/variables.tf seems to be used in dev deployments. We should have exactly one variables.tf file used in all venue deployments.

We have variables like hysds version, pcm version, etc. We should also have these in one place in terraform. Right now they are in several places.

[philipjyoon]

There is also a variables.tf in dev folder. This file surely is not necessary...