Move entries older than last year to changelog-old

The current changelog is *more than twice as long* as the "archive".
So it could really use some trimming. I propose to always keep the
current and previous years' entries.

Second half of the change: Remove the old entries (2012 and older).
Sketching SCM based on Job/Run.
Merge branch 'master' into SCM-Job
Fixing method compatibility checks.
Merge branch 'master' into SCM-Job
Need to retain original signature of _for(AbstractProject) for binary compatibility.
Trying to make it possible for a non-AbstractProject to use SCMTrigger.
Expanded SCMTriggerItem signature; trying to fix multiple-scms integration.
Use TaskListener rather than BuildListener for SCM methods.
Permit changelog generation to be skipped.
Allow changelogs to work with Run.
SCMListener should also work with Run.
A good time to get rid of deprecated return value from SCM.checkout.
Added SCMListener.onCheckout.
Also fixed compilation error from previous change.
Note.
Modernizing SCMListener registration.
Merge branch 'master' into SCM-Job

Conflicts:
	core/src/main/java/hudson/model/CauseAction.java
	core/src/main/java/hudson/triggers/SCMTrigger.java
Added annotations to kernel security classes.

Most of methods define @Nonnull inputs and outputs (the legacy behavior is mostly non-documented), but there're several exceptions

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>
Merge pull request #1266 from synopsys-arc-oss/refactoring_security_classes

Added annotations to kernel security classes.
Integrating a new version that supports multiple issue trackers