move entity_map_json to libipmid

entity_map_json is used by dbus-sdr sensor handling so it needs to be in
a common location or loading order matters. This change moves the file
from the ipmi20 provider library to libipmi, a common library.

Tested: Found that even though the dbus-sdr provider loads before
        ipmi20, it loads properly without missing symbols.

Change-Id: I9ab6833c78e6f3c89c02cf998ce0a36353059c3d
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
diff --git a/test/entitymap_json_unittest.cpp b/test/entitymap_json_unittest.cpp
index 4993351..5f31e1b 100644
--- a/test/entitymap_json_unittest.cpp
+++ b/test/entitymap_json_unittest.cpp
@@ -1,5 +1,4 @@
-#include "entity_map_json.hpp"
-
+#include <ipmid/entity_map_json.hpp>
 #include <ipmid/types.hpp>
 #include <nlohmann/json.hpp>