Implement integration/deploy tests (GHA)

[alexcasalboni]

I'm going to define a few custom Cfn stacks to cover the major deployment parameters:

PowerValues
visualizationURL
lambdaResource
totalExecutionTimeout
permissionsBoundary
payloadS3Bucket
payloadS3Key
layerSdkName
logGroupRetentionInDays
securityGroupIds
subnetIDs

Additionally, I'll create custom tests to make sure the deployed resources behave as intended (WIP, this might take a while).

[alexcasalboni]

Ok, first step completed, with a total of 5 stacks (including 1 with default params).

Next steps: make sure the deployed state machines work as intended.