[skeleton] Properly format debian/changelog using current datetime and author information
Reformat "context" dict to have it PEP8 compliant along the way (only white
space changes).
[utils] Encode Binary value in base64 for JSON export
In unittest_utils.py, use unittest2's TestCase instead of lgc.testlib one to
benefit from subTest API.
Closes #15409885.
[skeleton] Set Debian distribution to "UNRELEASED" in changelog
So to as to make it clear that changelog needs to be edited
before the Debian package may be published.