Migrate to bzlmod

[luispadron]

This PR updates the Bazel support for bzlmod. It updates Bazel to 6.4.0 and the targets for better external support:

• Adds manual tags to swift_library targets, this fixes bazel build //... failures since swift_library cannot import UIKit without being part of a top-level target like ios_framework.
• Adds public visibility to the Paralayout swift_library this is useful for consumers who would like to package the library in a different context, say, a static framework or application.
• Updates CI to use bazel test //... so it tests everything
• Ran buildifier -r . to reformat all Bazel files

[NickEntin]

Should this be "1.0.0"?

[luispadron]

We wouldn't update this version in main directly (see example), it gets updated automatically based on when a release is made once we start using: https://github.com/bazel-contrib/publish-to-bcr