[bazel] Add .bazelignore file.
[bazel] Add .bazelignore file.

Ignore all node_modules directories (except //infra-sk/node_modules, which is managed by the rules_nodejs toolchain) to prevent Bazel BUILD files included in some NPM packages from interfering with our build.

Change-Id: I08e85a7d496f2cf6f79a0383a99782fce19c6ebc
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/343562
Reviewed-by: Leandro Lovisolo <f558143c2568be8d55575d13f30a1fc5cb8009d5@google.com>
Reviewed-by: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>
Commit-Queue: Leandro Lovisolo <f558143c2568be8d55575d13f30a1fc5cb8009d5@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot