add missing includes (#5691)

* add missing includes

Building without precompiled header support revealed some missing
includes that are added with this change for code health purposes.
Those missing includes were hidden by precompiled header support due to
the fact that the precompiled header file provides some definitions
despite not being defined in directly or indirectly included header
files.

src/libslic3r/GCode/Thumbnails.cpp

@@ -1,10 +1,12 @@
 #include "Thumbnails.hpp"
 #include "../miniz_extension.hpp"
+#include "format.hpp"
 
 #include <qoi/qoi.h>
 #include <jpeglib.h>
 #include <jerror.h>
 #include <vector>
+#include <boost/algorithm/string.hpp>
 
 namespace Slic3r::GCodeThumbnails {
 

src/libslic3r/GCode/Thumbnails.hpp

@@ -4,6 +4,7 @@
 #include "../Point.hpp"
 #include "../PrintConfig.hpp"
 #include "ThumbnailData.hpp"
+#include "../enum_bitmask.hpp"
 
 #include <vector>
 #include <memory>

src/libslic3r/PrintConfig.cpp

@@ -2,6 +2,7 @@
 #include "ClipperUtils.hpp"
 #include "Config.hpp"
 #include "I18N.hpp"
+#include "format.hpp"
 
 #include "GCode/Thumbnails.hpp"
 #include <set>