Fix --ignore-dependencies with stack_output

[ngfgrant]

This commit fixes an issue where a users attempts to launch a single
stack that utilises the stack_output_resolver with the
--ignore-dependencies.

Previously, with --ignore-dependencies set, any dependencies that arose
through !stack_output_resolver would not be added to
stack.dependencies and the next() function in
StackOutput.resolve() would raise a StopIteration as the
stack.dependencies list would be empty.

This commit handles the stack_output by utilising the argument passed
into stack_output.

[Resolves #778]

PR Checklist

• Wrote a good commit message & description [see guide below].
• Commit message starts with [Resolve #issue-number].
• Added/Updated unit tests.
• Added/Updated integration tests (if applicable).
• All unit tests (make test) are passing.
• Used the same coding conventions as the rest of the project.
• The new code passes flake8 (make lint) checks.
• The PR relates to only one subject with a clear title.
  and description in grammatically correct, complete sentences.

Approver/Reviewer Checklist

• Before merge squash related commits.

Other Information

Guide to writing a good commit

[ngfgrant]

There maybe an issue with this implementation as it assumes the region and profile of the stack in stack_output is the same as the stack calling it.

[ngfgrant]

I can confirm that it is an issue :/