A *lot* of import fixes for flatpak (#3909)

* A *lot* of import fixes for flatpak

Aside, thank you @hadess for the majority of these fixes. You are the
base point for a lot of issues fixed during the creation of this
flatpak.

* Use slic3r::load_string_file

Boost 1.84 removed `boost::fs::load_string_file` so use the func located
in Utils.hpp

src/slic3r/GUI/Gizmos/GLGizmoBase.hpp

@@ -15,6 +15,8 @@
 
 #include <cereal/archives/binary.hpp>
 
+#include <wx/event.h>
+
 #define ENABLE_FIXED_GRABBER 1
 
 class wxWindow;

src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.cpp

@@ -15,9 +15,9 @@
 #include "slic3r/GUI/GUI.hpp"
 #include "slic3r/Utils/UndoRedo.hpp"
 
-
 #include <GL/glew.h>
 
+#include <boost/log/trivial.hpp>
 
 namespace Slic3r::GUI {
 

src/slic3r/GUI/Gizmos/GLGizmoText.cpp

@@ -6,7 +6,7 @@
 #include "slic3r/GUI/ImGuiWrapper.hpp"
 #include "slic3r/GUI/GUI_ObjectList.hpp"
 #include "slic3r/GUI/Plater.hpp"
-
+#include "libslic3r/ClipperUtils.hpp"
 #include "libslic3r/Geometry/ConvexHull.hpp"
 #include "libslic3r/Model.hpp"
 
@@ -14,6 +14,8 @@
 
 #include <numeric>
 
+#include <boost/log/trivial.hpp>
+
 #include <GL/glew.h>
 
 #ifndef IMGUI_DEFINE_MATH_OPERATORS