[doc] Remove legacy as irrelevant

doc/index.rst

@@ -50,7 +50,6 @@ Users Guide
     pad_intro
     vanilla_pad_intro
     vanilla_pad_features
-    legacy
 
 
 Reference Manual

doc/legacy.rst

-.. vim: set fileencoding=utf-8 :
-.. author: Yannick Dayer <yannick.dayer@idiap.ch>
-.. date: 2020-11-27 15:30:51 +01
-
-.. _bob.pad.base.legacy:
-
-================================
- Using legacy bob.pad utilities
-================================
-
-.. todo::
-
-   legacy adaptors:
-
-      - db connector
-      - legacy wrappers
-
-   Look at bob.bio.base legacy