Add ExpandMode to GetModuleContentOption

[wata727]

See terraform-linters/tflint#1537

terraform-linters/tflint#1537 added support for expanding blocks with the count/for_each meta-arguments. This changes the behavior of the IncludeNotCreated option of GetModuleContent.

If the IncludeNotCreated option is set, resources with count = 0 or for_each = {} will be ignored and blocks will not be expanded. For example, a resource with count = 2 will only return one block, and each.* and count.index will not be evaluated.

This behavior is not intuitive from the option name, so rename it to ExpandMode. ExpandMode corresponds to the IncludeNotCreated option as follows:

• tflint.ExpandModeExpand
  • IncludeNotCreated = false
• tflint.ExpandModeNone
  • IncludeNotCreated = true

The IncludeNotCreated option is still available, but deprecated. It will be removed in a future version.