Add new safe Buffer and Image types containing bound memory

[Rua]

Changelog:

### Breaking changes
Changes to buffers and images:
- `UnsafeBuffer` and `UnsafeImage` are renamed to `RawBuffer` and `RawImage`.
- `UnsafeBufferCreateInfo` and `UnsafeImageCreateInfo` are renamed to `BufferCreateInfo` and `ImageCreateInfo`.
- `ImageCreateInfo` now takes a `flags` instead of separate booleans.
- Replaced the various unsafe `*_linear_layout` methods of `UnsafeImage` with a safe `subresource_layout` method. The `LinearLayout` struct is renamed to `SubresourceLayout` to match.
- Added mostly-safe `bind_memory` methods to these two types. These take `self` by value, and return `Buffer` and `Image` on success.
- Added `Buffer` and `Image` types, which represent buffers and images that have had memory bound to them. This memory can be retrieved using the `memory()` method.
- Most previous uses of `UnsafeBuffer` and `UnsafeImage` now use `Buffer` and `Image` instead.

### Additions
- Added a `flags` field to `BufferCreateInfo`. This contains no flags yet, but will in the future.
- Added the `disjoint` flag to `ImageCreateFlags`. This flag is used in combination with multi-planar images, to bind separate memory to each plane of the image. It is not yet supported for the higher-level image types.

This is another step towards reducing the number of buffer and image types that are needed, and also makes binding memory mostly safe. Type safety is used to ensure that Buffer and Image always have memory bound to them. Once sparse binding is introduced, this will not fully be the case, since bindings can be made and unmade at any time; sparse resources will therefore require runtime checks.

@marc0246 There are some considerations in this PR that may affect your memory allocator code:

• The disjoint flag is added, which never allows dedicated allocations (VUID-VkMemoryDedicatedAllocateInfo-image-01797). Images that were created with this flag don't have one single MemoryRequirements, but rather two or three (for each plane). The memory_requirements method for images therefore now returns a slice. The newly introduced ImageMemory type also has a vector to hold all the allocations.
• MemoryRequirements was missing the requires_dedicated_allocation flag, which this PR adds. The allocator needs to ensure that when this flag is set, either a dedicated allocation is made or it errors out.

[marc0246]

Amazing! I love the that you renamed the Unsafe* types while on it, since that's not really a convention that exists. Granted those types were named long before anything resembling conventions materialized haha.

[AustinJ235]

Looks great!