Move Image/ImageChunk/PatchChunk declaration into header files

1. Move the declaration of the Image classes to the header file to make
testing easier.
2. Also move rangeset.h to bootable/recovery to allow access in imgdiff.

Test: recovery component test
Change-Id: I68a863e60a3f2e7ae46ee48f48eb15391f5f4330

tests/unit/rangeset_test.cpp

@@ -21,7 +21,7 @@
 
 #include <gtest/gtest.h>
 
-#include "updater/rangeset.h"
+#include "rangeset.h"
 
 TEST(RangeSetTest, Parse_smoke) {
   RangeSet rs = RangeSet::Parse("2,1,10");