Fork the Xcode rules from Bazel built-in Starlark into `apple_support`

[brentleyjones]

PiperOrigin-RevId: 631018102 (cherry picked from commit f1bbadc4aef7b62450b5db96b05c3da6e337900c)

[brentleyjones]

These new rules only work with Bazel 8. We should:

1. Add a feature to bazel_features so people can detect the apple_common.XcodeVersionConfig signature change and the addition of apple_fragment.xcode_version_flag
2. Error early if someone tries to use these rules on an unsupported Bazel version

[luispadron]

@brentleyjones @keith I rebased this and added checks for the bazel feature that's required. Mind taking a look?