Added ImageFile close()

[radarhere]

This is part of #8362 - I'm hoping to break down that PR into easier-to-review chunks.

1. Image's close() starts out with file handling.
   

   Pillow/src/PIL/Image.py

   Lines 632 to 637 in cf7dd2f

   	if hasattr(self, "fp"):
   	try:
   	self._close_fp()
   	self.fp = None
   	except Exception as msg:
   	logger.debug("Error closing: %s", msg)

   
   Since file handling is only part of ImageFile, this PR moves that code into a new ImageFile close() method that then calls super().close() to return to the rest of the method.

2. Similarly, Image's _close_fp() can be moved to ImageFile for the same reason.
   

   Pillow/src/PIL/Image.py

   Lines 606 to 612 in cf7dd2f

   	def _close_fp(self):
   	if getattr(self, "_fp", False):
   	if self._fp != self.fp:
   	self._fp.close()
   	self._fp = DeferredError(ValueError("Operation on closed image"))
   	if self.fp:
   	self.fp.close()