Creates a new Unpacker protocol that defines a single method
```
func unpack(_ image: Image, for platform: Platform, at path: URL, progress: ProgressHandler?) async throws -> Mount
```
This change also removes the `unpack(...)` method from the Image type.
Before
```
let mount = try await image.unpack(for: platform, at: path)
```
After
```
let unpacker = EXT4Unpacker(blockSizeInBytes: 2.gib())
let mount = try await unpacker.unpack(image, for: platform, at: path)
```
---------
Signed-off-by: Aditya Ramani <a_ramani@apple.com>
This change adds documentation to quite a few existing public types that
didn't have a blurb before.
Additionally, this fixes a couple things that I think either didn't make
sense when going to document them:
- Rename ConnectionStream to VsockConnectionStream. This type only
functions for vsock connections.
- Deletes NsLock+Closure. This was not used anywhere.
- Rename ContainerizationOCI/Config.swift to ImageConfig.swift.
Signed-off-by: Danny Canter <danny_canter@apple.com>