Add skeleton architecture for displaying custom splash screen

fusee/fusee-secondary/src/splash_screen.c

@@ -0,0 +1,17 @@
+#include "utils.h"
+#include "splash_screen.h"
+#include "sd_utils.h"
+#include "lib/printk.h"
+#include "display/video_fb.h"
+
+void display_splash_screen_bmp(const char *custom_splash_path) {
+    unsigned char *splash_screen = g_default_splash_screen;
+    if (custom_splash_path != NULL && custom_splash_path[0] != '\x00') {
+        if (!read_sd_file(splash_screen, sizeof(g_default_splash_screen), custom_splash_path)) {
+            printk("Error: Failed to read custom splash screen from %s!\n", custom_splash_path);
+            generic_panic();
+        }
+    }
+    
+    /* TODO: Display the splash screen. It should be a pointer to a BMP, at this point. */
+}