feat(Core): Updating to AWS SDK for Swift 1.0.0

[ruisebas]

Description

This PR upgrades the underlying AWS SDK for Swift dependency to their GA version: 1.0.0.

The vast majority of changes are just types being renamed or moved to different packages, but some business logic had to change here and there. Some of them include:

• Pretty much all SDK clients now need a signingRegion besides the region, so that parameter has been added.
• CredentialsProviding has been replaced with AWSCredentialIdentityResolver for all SDK clients, so our types have been modified accordingly
• As per usual, our customPresignURL extension to UploadPartInput had to be re-tweaked to generate a valid URL.
• All SDK Models lost their conformance to Codable, so we had to manually add it back for some types, mainly Pinpoint and Transcribe, as our operations relied on that.
  • This also pretty much broke AmplifyStringConvertible, which had to be fully re-written. It's a non-public debug-only utility anyways.
• While running Storage's integration tests, some issues were discovered with multipart uploads:
  • If a part failed to upload, instead of it being re-tried or the operation failing, nothing would happen and the execution would remain stuck waiting.
  • If an upload was aborted, awaiting for its value would still return a valid key instead of throwing, even though the upload was not completed.
  • I've wrapped all test uploads in Tasks that wait for expectations, so we don't hang the test if something goes wrong and instead just fail it with missing expectation, allowing for easy retries without having to wait for the 30 minutes timeout.

General Checklist

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• All integration tests pass
  • 
  • 
  • 
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• New or updated tests include Given When Then inline code documentation and are named accordingly testThing_condition_expectation()
• If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.