Refactor of bmcImages

bmcImages were in image_verify.hpp but it is used not only in image
verification, but elsewhere.

Move it into a more generic header file, images.hpp, so it makes more
clear that users of bmcImages include images.hpp instead of
image_verify.hpp

Tested: Verify the code pass the build.

Change-Id: If9adf315eee9047d9d08ab93ed7c0ff3c97f7a1e
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/activation.cpp b/activation.cpp
index 421902a..863ea56 100644
--- a/activation.cpp
+++ b/activation.cpp
@@ -1,4 +1,5 @@
 #include "activation.hpp"
+#include "images.hpp"
 #include "item_updater.hpp"
 #include "serialize.hpp"
 #include <phosphor-logging/log.hpp>