Add support for CloudFormation templates as files

CloudFormation templates as inputs are difficult to manage
due to their size, and being embedded in another yaml file.

This change allows moving CloudFormation templates to their own
file template in the root of the project where they can be autodiscovered
by Flowzone and deployed.

It also allows us to modify CF templates on repositories that otherwise
have push restrictions applied to the .github directories.

Change-type: minor
Signed-off-by: Kyle Harding <[email protected]>

Author: klutchell

.github/workflows/flowzone.yml

@@ -167,28 +167,8 @@ jobs:
       # Required: false
       aws_iam_role: ${{ vars.AWS_IAM_ROLE || '' }}
 
-      # AWS CloudFormation templates to deploy (e.g.)
-      # ```
-      # {
-      # "stacks": [
-      # {
-      # "name": "foo",
-      # "template": "aws/bar.yaml",
-      # "tags": [
-      # "Name=foo",
-      # "Environment=${FOO}"
-      # ],
-      # "capabilities": [
-      # "CAPABILITY_IAM",
-      # "CAPABILITY_NAMED_IAM"
-      # ]
-      # },
-      # ...
-      # ]
-      # }
-      # ```
-      # * assumes `aws/bar.yaml` exists.
-      # * `${ENVVARS}` injected at runtime from `vars` and `secrets` contexts
+      # This input is deprecated. To deploy CloudFormation stacks, create a
+      # `aws-cf-templates.yaml` file in the root of the repository.
       # Type: string
       # Required: false
       cloudformation_templates: