Fix library class equality across template and steps

[steven-terrana]

PR Details

fixes #279.

Resolves a bug involving class equivalency between steps and the template.

Description

While you could import a library class everywhere, it was actually a different version of that class due to disparate classloaders being used.

This PR resolves that by leveraging a common classloader across the pipeline template and each library step.

this also changes the initialization order of JTE.

Previously, it was:

1. aggregate pipeline configs
2. inject primitives
3. determine pipeline template
4. create and return CpsFlowExecution

it is now:

1. aggregate pipeline configs
2. determine pipeline template
3. create CpsFlowExecution
4. inject primitives
5. return CpsFlowExecution

This change has no impact on end-users but allows JTE to pass the actual CpsFlowExecution to TemplatePrimitiveInjectors.

How Has This Been Tested

Tests added that reproduce failure.
Tests pass now.

Types of Changes

• Added Unit Testing
• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have added the appropriate label for this PR
• If necessary, I have updated the documentation accordingly.
• All new and existing tests passed.