[Helper] FileRepository::findFile(): use the list of paths when given a dotted path

[fredroy]

Strangely, findFile, when given a dotted path to find, was not using its own list of paths and only use the current working directory. Which cause problems, especially with python3 scenes

Bonus, renaming the member vpath because it was confusing + using foreach loops

[with-all-tests]

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[fredroy]

[ci-build][with-all-tests]