Auto-generate Package.swift for service clients

[jbelkins]

Describe the feature

Every service client that is generated should be generated with a Package.swift manifest file that defines it as its own Swift package, along with its dependencies.

(We do already generate a package manifest in codegen, so that existing capability may be used to generate a Package.swift if it is updated to latest specs.)

The manifest should be generated with correct dependencies specified for the SDK & smithy-swift modules that it references in code.

The existing Package.swift is typically not copied over in the "build SDK" stage with existing automation. The Package.swift should be verified to work, but we're not going to use it at this time - it will be relied on in a later task.

Use Case

To support individual distribution of service clients by providing them with their own package manifest.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change