Began refactoring target descriptor structs.

This is incomplete - a partial commit of a substantial peice of work

src/Targets/TargetPeripheralDescriptor.hpp

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <string>
+#include <map>
+#include <optional>
+#include <functional>
+#include <string_view>
+
+#include "TargetRegisterGroupDescriptor.hpp"
+
+namespace Targets
+{
+    struct TargetPeripheralDescriptor
+    {
+    public:
+        std::string key;
+        std::string name;
+        std::map<std::string, TargetRegisterGroupDescriptor, std::less<void>> registerGroupDescriptorsByKey;
+
+        TargetPeripheralDescriptor(
+            const std::string& key,
+            const std::string& name,
+            const std::map<std::string, TargetRegisterGroupDescriptor, std::less<void>>& registerGroupDescriptorsByKey
+        );
+
+        std::optional<std::reference_wrapper<const TargetRegisterGroupDescriptor>> tryGetRegisterGroupDescriptor(
+            std::string_view keyStr
+        ) const;
+
+        const TargetRegisterGroupDescriptor& getRegisterGroupDescriptor(std::string_view key) const;
+    };
+}