Fixes #2151 Add distinction between PK-Sim and extension modules

[rwmcintosh]

Fixes #2151

Description

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Type of change

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• 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 not work as expected)
• This change requires a documentation update
• Algorithm update - updates algorithm documentation/questions/answers etc.
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How Has This Been Tested?

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• Integration tests
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• No tests required

Reviewer checklist

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• Check if the code is well documented
• Check if the behavior is what is expected
• Check if the code is well tested
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Questions (if appropriate):

[msevestre]

Remove the junk in the project file

[msevestre]

remove