Store original position of text box

This stores the original x-position and y-position of the text box, and
when a text box gets repositioned, it will use those unless a crewmate
position overrides it.

This is the original position of the text box, before centering or
crewmate position is considered.

This fixes a bug where a cutscene text box can be "shifted" from its
normal position via CTRL+F8 cycling if there is a translation that is
too long for the screen and thus gets pushed by adjust(). I tested this
with the text box in the Comms Relay cutscene that starts with "If YOU
can find a teleporter".

This is not applicable to function-based translations
(TEXTTRANSLATE_FUNCTION), because the responsibility of correctly
positioning the text box resides with the function.

desktop_version/src/Graphics.cpp

@@ -3344,6 +3344,8 @@ void Graphics::textboxoriginalcontextauto(void)
     {
         context.script_name = script.scriptname;
     }
+    context.x = textboxes[m].xp;
+    context.y = textboxes[m].yp;
 
     textboxes[m].original = context;
 }