nvidia-gpu: add entity-manager support

The commit add support for reading of the entity-manager configurations
to the gpu dbus sensor app.

Tested.

Build an image for gb200nvl-obmc machine with the following patches
cherry picked. This patches are needed to enable the mctp stack.

https://gerrit.openbmc.org/c/openbmc/openbmc/+/79312
https://gerrit.openbmc.org/c/openbmc/openbmc/+/79422

Copy the gpusensor app and run it.
```
root@gb200nvl-obmc:~# ./nvidiagpusensor
```

The app is detecting entity-manager configuration on gb200nvl-obmc
machine. The app is also able to detect all the endpoints from the mctp
service dbus tree.

Change-Id: I05a0597964bcc0c135484fed714b6f677adc5891
Signed-off-by: Harshit Aghera <haghera@nvidia.com>
diff --git a/src/Utils.hpp b/src/Utils.hpp
index 8cfdddd..037c127 100644
--- a/src/Utils.hpp
+++ b/src/Utils.hpp
@@ -43,8 +43,9 @@
 const std::regex illegalDbusRegex("[^A-Za-z0-9_]");
 
 using BasicVariantType =
-    std::variant<std::vector<std::string>, std::string, int64_t, uint64_t,
-                 double, int32_t, uint32_t, int16_t, uint16_t, uint8_t, bool>;
+    std::variant<std::vector<std::string>, std::vector<uint8_t>, std::string,
+                 int64_t, uint64_t, double, int32_t, uint32_t, int16_t,
+                 uint16_t, uint8_t, bool>;
 using SensorBaseConfigMap =
     boost::container::flat_map<std::string, BasicVariantType>;
 using SensorBaseConfiguration = std::pair<std::string, SensorBaseConfigMap>;