SDK file cleanup (remove non-darty build artifacts)

[pq]

The SDK currently ships with lots of non-dart resources that are essentially build artifacts (e.g., .c, .cc, .h files, etc) and are distracting to the end-user. It would be great to filter these out during the build and present the user with only legitimate SDK files of interest.

[dgrove]

The biggest offenders:

top-level has stamp files
html (has templates, idl, scripts, conf)

[dgrove]

fixed in r12968 and r12980.

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Added Fixed label.

[anders-sandholm]

Removed Area-Build label.
Added Area-Infrastructure label.