Migrate to Bzlmod.

[SanjayVas]

This updates Bazel to 6.4.0.

[wfa-reviewable]

This change is 

[stevenwarejones]

Reviewed 4 of 7 files at r1, all commit messages.
Reviewable status: 4 of 7 files reviewed, 2 unresolved discussions (waiting on @SanjayVas)

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.bazelrc line 4 at r1 (raw file):

common --enable_bzlmod
# TODO(@SanjayVas): Update this when the repo has been moved to the WFA org.
common --registry=https://github.com/SanjayVas/bazel-registry/main/

what is this for?

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build/non_module_deps.bzl line 26 at r1 (raw file):

        urls = [
            # 2023-07-30
            "https://github.com/google/private-join-and-compute/archive/f77f26fab7f37e5e1e2d43250662c0281bd7fa4a.tar.gz",

shouldn't this be coming from common-cpp?

[SanjayVas]

Reviewable status: 4 of 7 files reviewed, 2 unresolved discussions (waiting on @stevenwarejones)

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.bazelrc line 4 at r1 (raw file):

Previously, stevenwarejones (Steven Ware Jones) wrote…

what is this for?

This is to include the Bazel registry for our modules in addition to the Bazel Central Registry (BCR).

Sorry, I hadn't meant to send this out for review yet as it's not a leaf repo and therefore currently depends on repos under my GitHub user. I'll send out PRs later for setting up the modules and Bazel registry in the WFA org.

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build/non_module_deps.bzl line 26 at r1 (raw file):

Previously, stevenwarejones (Steven Ware Jones) wrote…

shouldn't this be coming from common-cpp?

No.

1. Bzlmod uses strict dependency visibility, you have to indicate all direct dependencies even if they are also included transitively.
2. common-cpp doesn't actually use this, so it does not have this dependency post-migration. See Migrate to Bzlmod. common-cpp#40

[stevenwarejones]

Reviewed all commit messages.
Reviewable status: 4 of 7 files reviewed, 2 unresolved discussions

[stevenwarejones]

Reviewed 2 of 7 files at r1, 2 of 2 files at r3, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @SanjayVas)

[stevenwarejones]

Reviewed 2 of 2 files at r4, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @SanjayVas)

[stevenwarejones]

Reviewed 1 of 1 files at r5, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @SanjayVas)

[SanjayVas]

I'm going to wait for pending PR #39 to be merged to avoid disruption.