Remove bitbake-layer example

recipes-example/example/example_0.1.bb

-SUMMARY = "bitbake-layers recipe"
-DESCRIPTION = "Recipe created by bitbake-layers"
-LICENSE = "MIT"
-
-python do_display_banner() {
-    bb.plain("***********************************************");
-    bb.plain("*                                             *");
-    bb.plain("*  Example recipe created by bitbake-layers   *");
-    bb.plain("*                                             *");
-    bb.plain("***********************************************");
-}
-
-addtask display_banner before do_build