Base: Update some icons for color, quality and consistency

And remove unused filetypes

Userland/Applications/HexEditor/CMakeLists.txt

@@ -5,5 +5,5 @@ set(SOURCES
     main.cpp
 )
 
-serenity_app(HexEditor ICON app-hexeditor)
+serenity_app(HexEditor ICON app-hex-editor)
 target_link_libraries(HexEditor LibGUI)

Userland/Applications/HexEditor/HexEditorWidget.cpp

@@ -227,7 +227,7 @@ HexEditorWidget::HexEditorWidget()
     }));
 
     auto& help_menu = menubar->add_menu("Help");
-    help_menu.add_action(GUI::CommonActions::make_about_action("Hex Editor", GUI::Icon::default_icon("app-hexeditor"), window()));
+    help_menu.add_action(GUI::CommonActions::make_about_action("Hex Editor", GUI::Icon::default_icon("app-hex-editor"), window()));
 
     GUI::Application::the()->set_menubar(move(menubar));
 

Userland/Applications/HexEditor/main.cpp

@@ -43,7 +43,7 @@ int main(int argc, char** argv)
         return 1;
     }
 
-    auto app_icon = GUI::Icon::default_icon("app-hexeditor");
+    auto app_icon = GUI::Icon::default_icon("app-hex-editor");
 
     auto window = GUI::Window::construct();
     window->set_title("Hex Editor");