Cleanup: Remove outdated guardedalloc guide

This was already very outdated before and even more so now. The docs in
MEM_guardedalloc.h cover this information already.

Pull Request: https://projects.blender.org/blender/blender/pulls/151387

doc/guides/blender-guardedalloc.txt

@@ -1,57 +0,0 @@
-MEMORY MANAGEMENT IN BLENDER (guardedalloc)
--------------------------------------------
-
-NOTE: This file does not cover memutil and smart pointers and reference counted
-      garbage collection, which are contained in the memutil module.
-
-Blender takes care of dynamic memory allocation using a set of own functions
-which are recognizable through their MEM_ prefix. All memory allocation and
-deallocation in blender is done through these functions.
-
-The following functions are available through MEM_guardedalloc.h:
-
-For normal operation:
----------------------
-
-void *MEM_[mc]allocN(unsigned int len, char * str);
-
-- nearest ANSI counterpart: malloc()
-- str must be a static string describing the memory block (used for debugging
-memory management problems)
-- returns a memory block of length len
-- MEM_callocN clears the memory block to 0
-
-void *MEM_dupallocN(void *vmemh);
-
-- nearest ANSI counterpart: combination malloc() and memcpy()
-- returns a pointer to a copy of the given memory area
-
-short MEM_freeN(void *vmemh);
-
-- nearest ANSI counterpart: free()
-- frees the memory area given by the pointer
-- returns 0 on success and !=0 on error
-
-int MEM_allocN_len(void *vmemh);
-
-- nearest ANSI counterpart: none known
-- returns the length of the given memory area
-
-For debugging:
---------------
-
-void MEM_set_error_stream(FILE*);
-
-- this sets the file the memory manager should use to output debugging messages
-- if the parameter is NULL the messages are suppressed
-- default is that messages are suppressed
-
-void MEM_printmemlist(void);
-
-- if err_stream is set by MEM_set_error_stream() this function dumps a list of all
-currently allocated memory blocks with length and name to the stream
-
-bool MEM_consistency_check(void);
-
-- this function tests if the internal structures of the memory manager are intact
-- returns 0 on success and !=0 on error