kernel/elf: Use extended_image_info instead of reading runtime_loader structures.

This solves some TODOs and allows image_debug_lookup_user_symbol_address
to be dropped entirely. It should also fix reading symbols from binaries
that have multiple TEXT regions, and most functions are not in the first.

headers/private/kernel/kimage.h

@@ -56,9 +56,6 @@ struct image* image_iterate_through_images(image_iterator_callback callback,
 struct image* image_iterate_through_team_images(team_id teamID,
 					image_iterator_callback callback, void* cookie);
 
-extern status_t image_debug_lookup_user_symbol_address(Team *team,
-					addr_t address, addr_t *_baseAddress, const char **_symbolName,
-					const char **_imageName, bool *_exactMatch);
 extern status_t image_init(void);
 
 // user-space exported calls