Refactor flags and add Font Manager to settings editor

Simplified `ExperimentFlags` by removing unused flags and updated
`Controller` to no longer inherit from it. Refactored `FlagsMenu`
to separate flag categories into individual methods for better
organization. Enhanced settings editor with a new "Font Manager"
tab and updated `DrawGeneralSettings` to use the new flag category
methods. Added `DrawFontManager` function for font management.

src/app/core/common.h

@@ -56,12 +56,6 @@ class ExperimentFlags {
     // Attempt to run the dungeon room draw routine when opening a room.
     bool kDrawDungeonRoomGraphics = true;
 
-    // Use the new platform specific file dialog wrappers.
-    bool kNewFileDialogWrapper = true;
-
-    // Uses texture streaming from SDL for my dynamic updates.
-    bool kLoadTexturesAsStreaming = true;
-
     // Save dungeon map edits to the Rom.
     bool kSaveDungeonMaps = false;
 
@@ -113,10 +107,6 @@ class ExperimentFlags {
         "\n";
     result += "kDrawDungeonRoomGraphics: " +
               std::to_string(get().kDrawDungeonRoomGraphics) + "\n";
-    result += "kNewFileDialogWrapper: " +
-              std::to_string(get().kNewFileDialogWrapper) + "\n";
-    result += "kLoadTexturesAsStreaming: " +
-              std::to_string(get().kLoadTexturesAsStreaming) + "\n";
     result +=
         "kSaveDungeonMaps: " + std::to_string(get().kSaveDungeonMaps) + "\n";
     result += "kLogToConsole: " + std::to_string(get().kLogToConsole) + "\n";

src/app/core/controller.h

@@ -26,7 +26,7 @@ namespace core {
  * This class is responsible for managing the main window and the
  * main editor. It is the main entry point for the application.
  */
-class Controller : public ExperimentFlags {
+class Controller {
  public:
   bool IsActive() const { return active_; }
   absl::Status OnEntry(std::string filename = "");