Applications: Use pledge()

Add some basic pledges to the following apps:

- Calculator
- DisplayProperties
- FontEditor
- HexEditor
- PaintBrush

Applications/FontEditor/main.cpp

@@ -9,8 +9,18 @@
 
 int main(int argc, char** argv)
 {
+    if (pledge("stdio shared_buffer unix rpath cpath wpath fattr", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
     GApplication app(argc, argv);
 
+    if (pledge("stdio shared_buffer rpath cpath wpath", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
     RefPtr<Font> edited_font;
     String path;