[bazel] Use bazel to build task drivers

One very important, but agonizing to discover, change was
to go_repositories.bzl. Without it, we see cryptic errors like:
external/org_chromium_go_luci/cipd/api/cipd/v1/BUILD.bazel:22:17: no such package '@org_chromium_go_luci//go.chromium.org/luci/cipd/api/cipd/v1': BUILD file not found in directory 'go.chromium.org/luci/cipd/api/cipd/v1' of external repository @org_chromium_go_luci. Add a BUILD file to a directory to mark it as a package. and referenced by '@org_chromium_go_luci//cipd/api/cipd/v1:api_go_proto'

The rest of these changes are very similar to
https://skia-review.googlesource.com/c/buildbot/+/514074
which also has justification for the use of task drivers,
even in a Bazel-driven world.

All the BUILD.bazel files under infra/bots/task_drivers were
generated by Gazelle.

Note that the infra/bots/BUILD.bazel can happily build and
package up the task drivers from the infra repo. The old
build_task_drivers tasks did this too, because we have some
task drivers that are used in both repos.

Change-Id: I13c46c62bc7a6a4bfe7935b28efbfb34caabb6f2
Bug: skia:12541
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/515296
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
diff --git a/go_repositories.bzl b/go_repositories.bzl
index 3b22a99..47239a3 100644
--- a/go_repositories.bzl
+++ b/go_repositories.bzl
@@ -3332,6 +3332,9 @@
     )
     go_repository(
         name = "org_chromium_go_luci",
+        # This module is distributed with pre-generated .pb.go files, so we disable generation of
+        # go_proto_library targets.
+        build_file_proto_mode = "disable",
         importpath = "go.chromium.org/luci",
         sum = "h1:Qe0s5XpxD36QC+7OVnc1Ce8igF3sfTo3f3ad4WKEpNo=",
         version = "v0.0.0-20201121231857-b9ab316d7198",