Make LCD_TIMEOUT_TO_STATUS configurable

As suggested in
https://github.com/MarlinFirmware/Marlin/issues/5570#issuecomment-283059
065

Marlin/Conditionals_post.h

@@ -726,4 +726,9 @@
     #define HAS_FOLDER_SORTING (FOLDER_SORTING || ENABLED(SDSORT_GCODE))
   #endif
 
+  // LCD timeout to status screen default is 15s
+  #ifndef LCD_TIMEOUT_TO_STATUS
+    #define LCD_TIMEOUT_TO_STATUS 15000
+  #endif
+
 #endif // CONDITIONALS_POST_H

Marlin/Configuration_adv.h

@@ -425,6 +425,9 @@
 // On the Info Screen, display XY with one decimal place when possible
 //#define LCD_DECIMAL_SMALL_XY
 
+// The timeout (in ms) to return to the status screen from sub-menus
+//#define LCD_TIMEOUT_TO_STATUS 15000
+
 #if ENABLED(SDSUPPORT)
 
   // Some RAMPS and other boards don't detect when an SD card is inserted. You can work

Marlin/ultralcd.h

@@ -65,7 +65,6 @@
   #define LCD_ALERTMESSAGEPGM(x) lcd_setalertstatuspgm(PSTR(x))
 
   #define LCD_UPDATE_INTERVAL 100
-  #define LCD_TIMEOUT_TO_STATUS 15000
 
   #if ENABLED(ULTIPANEL)