test: add test_marker files for integ test components

[marofke]

Problem

Integration stack components were still creating 'LaunchTemplateName's that were not unique.

Solution

• added a cdk.json file to the root of the integ directory, which seemed to apply the feature flag correctly
• this required me to change the integ/scripts/bash/rfdk-integ-e2e.sh script to look for a test_marker file in each integ test component directory as it was causing issues since the script would try to run tests from the integ root
• reverted the change to add more information to the Bastion name in the test-tier component as it wasn't needed

Testing

• figured out how to synthesize locally, confirmed the template names were different (each snippet form a different component):

  "launchTemplateName": "RFDKIntegDLTestingTier1703111097634975852BastionLaunchTemplateE58D8C6C",
  "launchTemplateName": "RFDKIntegRQTestingTier1703111097634975852BastionLaunchTemplate6734337A",
  "launchTemplateName": "RFDKIntegWFTestingTier1703111097634975852BastionLaunchTemplate35EDE82F",
  "launchTemplateName": "RFDKIntegWFSTestingTier1703111097634975852BastionLaunchTemplate93E234E7",
  "launchTemplateName": "RFDKIntegSMTestingTier1703111097634975852BastionLaunchTemplate0BC146AF",

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