Add smart artifact find during upload

[rsora]

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• The PR has no duplicates (please search among the Pull Requests before creating one)
• The PR follows our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce?

(Originates from a fix for #641)
The CLI upload step searches also in fallback locations for artifacts to upload, in case these files are missing.

• What is the current behavior?

The CLI upload step assumes that the artifacts generated by the compile phase are also "exported" into the sketch folder (see the Java IDE export feature). This means that during the compile phase, the output files generated by the specific platform compiler are placed:

• in a temporary calculated path obtained via builder.GenBuildPath(sketchPath)

or

• in the user specified --build-path path
  And then "exported" (copied) into the sketch path.

This behavior could create issues for cores that do not implement correctly the "export" variables in the platform.txt, see for example this core in which you have the export recipe file extension .hex that is misaligned with the upload file extension .zip

Since the export feature is not fundamental in the Java IDE, 3rd party core maintainers are not forced to implement it or to implement it 100% correctly, so the CLI must take in account this aspect

• What is the new behavior?

The upload command search process is the following:

1. search the User specified importFile
2. search into the Sketch folder (for "exported" files)
3. search into the user specified --build-path (if passed during a compile --upload command)
4. search into temp compile folder (calculated using builder.GenBuildPath(sketchPath))

• Does this PR introduce a breaking change?

Not really, this change adds fallback strategies to the upload implementation that should be transparent for the user.

• Other information:

I assumed in this PR that artifact files in fallback paths are always in this form sketch.Name+".ino"+ext and not in the exported form sketch.Name + "." + fqbnSuffix + ext

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