Signing Service initial support (bugs 1070189, 1070191, 1070227)

Bug 1070189: Call the trunion API (not tested with servers yet)
Bug 1070191: Signing management command
Bug 1070227: Script to sign all existing add-ons
we usually (not always :/) use the lowercase version of this marker.
Please add a comment above to explain that this is the trick/hack you use to be able to launch this script standalone.