feat(policy network stack): Policies can now return the network stack

Policies can now return the network stack which allows the caller more
control over settings and running a solver against various levels of the
stack. Further, policies can return the partition function used as well
as a vector of enums which describe the structure of the network stack.

src/include/gridfire/engine/types/engine_types.h

@@ -1,4 +1,33 @@
 #pragma once
 
 #include "gridfire/engine/types/building.h"
-#include "gridfire/engine/types/reporting.h"
+#include "gridfire/engine/types/reporting.h"
+
+namespace gridfire {
+    enum class EngineTypes {
+        GRAPH_ENGINE,
+        ADAPTIVE_ENGINE_VIEW,
+        MULTISCALE_PARTITIONING_ENGINE_VIEW,
+        PRIMING_ENGINE_VIEW,
+        DEFINED_ENGINE_VIEW,
+        FILE_DEFINED_ENGINE_VIEW
+    };
+
+    inline std::string engine_type_to_string(const EngineTypes type) {
+        switch (type) {
+            case EngineTypes::GRAPH_ENGINE:
+                return "GraphEngine";
+            case EngineTypes::ADAPTIVE_ENGINE_VIEW:
+                return "AdaptiveEngineView";
+            case EngineTypes::MULTISCALE_PARTITIONING_ENGINE_VIEW:
+                return "MultiscalePartitioningEngineView";
+            case EngineTypes::PRIMING_ENGINE_VIEW:
+                return "PrimingEngineView";
+            case EngineTypes::DEFINED_ENGINE_VIEW:
+                return "DefinedEngineView";
+            case EngineTypes::FILE_DEFINED_ENGINE_VIEW:
+                return "FileDefinedEngineView";
+        }
+        return "UnknownEngineType";
+    }
+}