Closes #697

Implemented solution:

The solution relies on the search of a specific pattern for flask-based backend. First, all the possible candidates containing a __main__.py file are searched (original behavior), then from those candidates, the content of each of them is scanned to look for the pattern we generate from cloud harness. This avoid the inclusion of __main.py as arguments in the case of there is some third-party libraries included for local testing purpose that also own a __main__.py (e.g: matplotlib).

How to test this PR:

To reproduce the original issue, in the folder of a workflow (e.g: myapp) that needs to be included in the skaffold configuration, simply add a folder hierachie like this: myfolder/mysubfolder/__main__.py.
After a generation of the skaffold configuration, the entry in the skaffold.yml document for the overrides section should be:

overrides:
        apps:
          myapp:
            harness:
              deployment:
                args: [/usr/src/app/matplotlib/__main__.py]
                command: [python]

With the fix of this PR, the right path towards the __main__.py of the myapp workflow is now referenced.

Sanity checks:

• The pull request is explicitly linked to the relevant issue(s)
• The issue is well described: clearly states the problem and the general proposed solution(s)
• From the issue and the current PR it is explicitly stated how to test the current change
• The labels in the issue set the scope and the type of issue (bug, feature, etc.)
• All the automated test checks are passing
• All the linked issues are included in one milestone
• All the linked issues are in the Review/QA column of the board
• All the linked issues are assigned

Breaking changes (select one):

• The present changes do not change the preexisting api in any way
• This PR and the issue are tagged as a breaking-change

Possible deployment updates issues (select one):

• There is no reason why deployments based on CloudHarness may break after the current update
• This PR and the issue are tagged as alert:deployment

Test coverage (select one):

• Tests for the relevant cases are included in this pr
• The changes included in this pr are out of the current test coverage scope

Documentation (select one):

• The documentation has been updated to match the current changes
• The changes included in this PR are out of the current documentation scope

Nice to have (if relevant):

• Screenshots of the changes
• Explanatory video/animated gif