Import buildifier

This patch sets up buildifier to run as part of CI. It can also be run
manually via `//tools/lint:buildifier`.

As a consequence, I needed to make the whole repo conform.

Signed-off-by: Philipp Schrader <philipp.schrader@gmail.com>
Change-Id: Ic41c97b17255813b6c21aef40ab2f8a216683a2c
diff --git a/tools/lint/run-ci.sh b/tools/lint/run-ci.sh
index 48c0960..6228552 100755
--- a/tools/lint/run-ci.sh
+++ b/tools/lint/run-ci.sh
@@ -50,6 +50,10 @@
     "${tweaker}" ./go_deps.bzl
 }
 
+buildifier() {
+    ./tools/lint/buildifier
+}
+
 git_status_is_clean() {
     cd "${BUILD_WORKSPACE_DIRECTORY}"
     if ! git diff --quiet; then
@@ -65,6 +69,7 @@
     update_repos
     gazelle
     tweak_gazelle_go_deps
+    buildifier
     git_status_is_clean  # This must the last linter.
 )