Add support to calculate npm tree only by package-lock.json file

[asafambar]

• All tests passed. If this feature is not already covered by the tests, I added new tests.
• All static analysis checks passed.
• This pull request is on the dev branch.
• I used gofmt for formatting the code before submitting the pull request.

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This PR introduce more control on the possible ways npm tree is calculated:

1. create the tree (which is the "ls" command) only by the package-lock file, with no mater if node modules exists.
2. if package-lock exists, check if the package.json is more updated than the lock, if so, then recalculate th package-lock file.