Added Plugin support (#102)

* Build refactoring and initial plugin support

* Possibly fixed linux / mac build

* Added libdl to libglad build script

* Add glfw to imgui dependencies

* Refactored common functionality into "libimhex" for plugins

* Added plugin loading and example plugin

* Added proper API for creating a custom view and a custom tools entry with plugins

include/helpers/plugin_handler.hpp

@@ -0,0 +1,48 @@
+#pragma once
+
+#include "views/view.hpp"
+
+#include <string_view>
+
+namespace hex {
+
+    class Plugin {
+    public:
+        Plugin(std::string_view path);
+        ~Plugin();
+
+        void setImGuiContext(ImGuiContext *ctx) const;
+        View* createView() const;
+        void drawToolsEntry() const;
+
+    private:
+        using SetImGuiContextFunc = void(*)(ImGuiContext*);
+        using CreateViewFunc = View*(*)();
+        using DrawToolsEntryFunc = void(*)();
+
+        void *m_handle = nullptr;
+
+        SetImGuiContextFunc m_setImGuiContextFunction = nullptr;
+        CreateViewFunc m_createViewFunction = nullptr;
+        DrawToolsEntryFunc m_drawToolsEntryFunction = nullptr;
+
+    };
+
+    class PluginHandler {
+    public:
+        PluginHandler() = delete;
+
+        static void load(std::string_view pluginFolder);
+        static void unload();
+        static void reload();
+
+        static const auto& getPlugins() {
+            return PluginHandler::s_plugins;
+        }
+
+    private:
+        static inline std::string s_pluginFolder;
+        static inline std::vector<Plugin> s_plugins;
+    };
+
+}