Move vk_safe_struct to VUL

This code was being generated in both Vulkan-ValidationLayers
and Vulkan-ExtensionLayer. Further uses are on the horizon so
lets stop the copypasta.

Also, add functions to manipulate extension lists and pNext chains,
since many client layers have been doing that themselves.

scripts/generators/vulkan_object.py

@@ -1,8 +1,7 @@
 #!/usr/bin/python3 -i
 #
-# Copyright 2023 The Khronos Group Inc.
-# Copyright 2023 Valve Corporation
-# Copyright 2023 LunarG, Inc.
+# Copyright (c) 2023-2024 Valve Corporation
+# Copyright (c) 2023-2024 LunarG, Inc.
 #
 # SPDX-License-Identifier: Apache-2.0
 
@@ -33,7 +32,7 @@ class Extension:
     # Quotes allow us to forward declare the dataclass
     commands: list['Command'] = field(default_factory=list, init=False)
     enums:    list['Enum']    = field(default_factory=list, init=False)
-    bitmask:  list['Bitmask'] = field(default_factory=list, init=False)
+    bitmasks: list['Bitmask'] = field(default_factory=list, init=False)
     # Use the Enum name to see what fields are extended
     enumFields: dict[str, list['EnumField']] = field(default_factory=dict, init=False)
     # Use the Bitmaks name to see what flags are extended
@@ -65,6 +64,9 @@ class Handle:
 
     dispatchable: bool
 
+    def __lt__(self, other):
+        return self.name < other.name
+
 @dataclass
 class Param:
     """<command/param>"""
@@ -92,6 +94,9 @@ class Param:
     #   - VkStructureType sType
     cDeclaration: str
 
+    def __lt__(self, other):
+        return self.name < other.name
+
 class Queues(IntFlag):
     TRANSFER       = auto() # VK_QUEUE_TRANSFER_BIT
     GRAPHICS       = auto() # VK_QUEUE_GRAPHICS_BIT
@@ -153,6 +158,9 @@ class Command:
     #   (const VkInstanceCreateInfo* pCreateInfo, const VkAllocationCallbacks* pAllocator, VkInstance* pInstance);
     cFunctionPointer: str
 
+    def __lt__(self, other):
+        return self.name < other.name
+
 @dataclass
 class Member:
     """<member>"""
@@ -179,6 +187,9 @@ class Member:
     #   - VkStructureType sType
     cDeclaration: str
 
+    def __lt__(self, other):
+        return self.name < other.name
+
 @dataclass
 class Struct:
     """<type category="struct"> or <type category="union">"""
@@ -200,6 +211,9 @@ class Struct:
     extends: list[str] # Struct names that this struct extends
     extendedBy: list[str] # Struct names that can be extended by this struct
 
+    def __lt__(self, other):
+        return self.name < other.name
+
 @dataclass
 class EnumField:
     """<enum> of type enum"""
@@ -210,6 +224,9 @@ class EnumField:
     # some fields are enabled from 2 extensions (ex) VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR)
     extensions: list[Extension] # None if part of 1.0 core
 
+    def __lt__(self, other):
+        return self.name < other.name
+
 @dataclass
 class Enum:
     """<enums> of type enum"""
@@ -225,6 +242,9 @@ class Enum:
     # Unique list of all extension that are involved in 'fields' (superset of 'extensions')
     fieldExtensions: list[Extension]
 
+    def __lt__(self, other):
+        return self.name < other.name
+
 @dataclass
 class Flag:
     """<enum> of type bitmask"""
@@ -236,7 +256,10 @@ class Flag:
     zero: bool     # if true, the value is zero (ex) VK_PIPELINE_STAGE_NONE)
 
     # some fields are enabled from 2 extensions (ex) VK_TOOL_PURPOSE_DEBUG_REPORTING_BIT_EXT)
-    extensions: list[str] # None if part of 1.0 core
+    extensions: list[Extension] # None if part of 1.0 core
+
+    def __lt__(self, other):
+        return self.name < other.name
 
 @dataclass
 class Bitmask:
@@ -246,12 +269,17 @@ class Bitmask:
     protect: (str | None) # ex) VK_ENABLE_BETA_EXTENSIONS
 
     bitWidth: int # 32 or 64
+    returnedOnly: bool
+
     flags: list[Flag]
 
     extensions: list[Extension] # None if part of 1.0 core
     # Unique list of all extension that are involved in 'flag' (superset of 'extensions')
     flagExtensions: list[Extension]
 
+    def __lt__(self, other):
+        return self.name < other.name
+
 @dataclass
 class FormatComponent:
     """<format/component>"""