bzlmod support / Bazel 7.0

[jerrymarino]

Bazel 7 is dropping in november, this issue is about adding support for this and bzlmod. The new lockfile is also available in Bazel 6.3.0 so it'd be useful to leverage this as well.

Here's some relevant docs/reading:

1. Release 7.0.0 - December 2023 bazelbuild/bazel#18548
2. Feature request: Add support for Bzlmod bazel-ios/rules_ios#704
3. https://blog.bazel.build/2023/07/24/whats-new-with-bzlmod.html