Start verifying pipeline requests.

Use Apache http components directly in cube import pipeline, with attempt to use FileInputStream for streaming potentially large HTTP requests.

Try implementing with callable global to set things up and compiled class implementing drafter methods. Use test JSON files as responses.

Add configFileProvider and credentials binding plugins, for testing Jenkins stored parameters.

Add test based on https://github.com/mkobit/jenkins-pipeline-shared-libraries-gradle-plugin. Currently times-out after sending and receiving HTTP req/res.