util: Add vk_struct_helper.hpp

Move the vk_typemap_helper.h file in Vulkan-ValidationLayers over to this
repo with a different name to reflect the use of it

Changes from that include:
 * Rename the functions to be more obvious as to what they do
 * Placing them in the `vku` namespace
 * Adding the `InitStructHelper` class which deduces the type based on the
   variable that is being initialized
 * Compiler error if there is no corresponding sType

scripts/generate_source.py

@@ -25,6 +25,7 @@ def RunGenerators(api: str, registry: str, targetFilter: str) -> None:
     from generators.dispatch_table_generator import DispatchTableOutputGenerator
     from generators.enum_string_helper_generator import EnumStringHelperOutputGenerator
     from generators.format_utils_generator import FormatUtilsOutputGenerator
+    from generators.struct_helper_generator import StructHelperOutputGenerator
 
     # Build up a list of all generators and custom options
     generators = {
@@ -40,6 +41,10 @@ def RunGenerators(api: str, registry: str, targetFilter: str) -> None:
             'generator' : FormatUtilsOutputGenerator,
             'directory' : 'include/vulkan/utility',
         },
+        'vk_struct_helper.hpp' : {
+            'generator' : StructHelperOutputGenerator,
+            'directory' : 'include/vulkan/utility',
+        },
     }
 
     if (targetFilter and targetFilter not in generators.keys()):