Migrate from CocoaPods to Swift Package Manager and support Xcode 14.

[GetToSet]

This PR contains the following key changes:

1. Migrate from CocoaPods to Swift Package Manager, with the same third-party packages and versions.
2. The project is made ready for Xcode 14.
3. Test configuration is removed. This configuration is added by CocoaPods and tests run well with the Debug configuration.
4. Codesigning related configurations are hard to manage. All codesigning configurations are moved to .xcconfig files to make it easier to edit, compare and maintain.
5. Some duplicate configurations have been cleaned up. (Prefer inheriting configuration values from the project level rather than redefining the same value in the target level.)