[Swift] Using arrow swift package

### Describe the usage question you have. Please include as many useful details as possible.

What is the recommended way of consuming the arrow swift package for downstream usage? It does not seem possible to use a git package url directly? See https://stackoverflow.com/questions/48666237/swift-package-manager-dependency-in-a-repository-subdirectory

The mentioned submodule approach is not optimal, and the arrow repository is pretty massive overall. Do you have any alternative approach for using the swift bindings?

### Component(s)

Swift

Start with the Swift component and the linked Stack Overflow discussion about Swift Package Manager dependencies in repository subdirectories. No source file or test is named; done would be a documented, agreed recommendation for consuming the Swift package downstream without the non-optimal submodule approach.

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