Signingscript

Added
- added datadog statsd

Added
- updated `host.cert` for new ssl cert with >30day expiration :)

Added
- updated `host.cert` for new ssl cert

Added
- added `signingscirpt.createprecomplete` from [mozilla-central](https://hg.mozilla.org/mozilla-central/file/d3025e55dfc3/config/createprecomplete.py), and made it py3 compatible
- added a `remove_extra_files` to make sure we're not leaving any cruft behind in the extracted directories.

Changed
- widevine zip signing now extracts the entire zipfile
- regenerate the `precomplete` file after widevine signing, for complete updates. then upload a `precomplete.diff`.

Fixed
- pass in the .sig path in `sign_widevine_zip` as well.

Fixed
- pass in the .sig path now that `output_file` works in signtool