Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..
bazel: build/test almost everything
**What this PR does / why we need it**: Miscellaneous cleanups and bug fixes. The main motivating idea here was to make `bazel build //...` and `bazel test //...` mostly work. (There's a few reasons these still don't work, but we're a lot closer.)
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
/assign @BenTheElder @mikedanese @spxtr
Previously, kubeadm would use <ip>:<port> to construct a master
endpoint. This works fine for IPv4 addresses, but not for IPv6.
IPv6 requires the ip to be encased in brackets when being joined
to a port with a colon.
This patch updates kubeadm to support wrapping a v6 address with
[] to form the master endpoint url. Since this functionality is
needed in multiple areas, a dedicated util function was created.
Fixes: https://github.com/kubernetes/kubernetes/issues/48227
