Deprecate legacy AFF-L reference images; provide new reference .aff4l files conforming to AFF4-L Standard v1.0-ALPHA

[jbolas]

New pre-release AFF4-L Standard v1.0-ALPHA (initial public release of draft) reads in part:

"This document is intended for implementers of the AFF4 Logical (AFF4-L) forensic container, and is to be read as an explanation of the AFF4-L Canonical Reference Images v1.0. These are available via the AFF4 GitHub https://github.com/aff4/ReferenceImages/aff4l/ .
Where there is ambiguity or difference between what is stated in this document and the Reference Images, the reference images take precedence. Accordingly, this document may be updated to resolve any such differences."

and

"In the standard we refer to AFF4-L implementations which do not support this standard as Legacy AFF4-L implementations. Accordingly, the initial AFF4-L paper is also considered a legacy implementation."

Please consider:

• moving existing AFF4-L reference images created by Legacy AFF4-L implementations to a different folder, perhaps "AFF4-L_Legacy" or "AFF4-L_container-version-1.1".
• providing several new .aff4l reference images, container versioned 2.1, as canonical examples that conform with the new draft standard.

For implementers, canonical references will be a huge help.