app/gerrit: import OAuth provider and add SSO support

This change:

 - imports gerrit-oauth-provider from upstream
 - adds sso.hackerspae.pl support to it

Change-Id: I92e7053614a9297bf1ced3aac044c0002acd836a
diff --git a/app/gerrit/gerrit-oauth-provider/tools/bzl/BUILD b/app/gerrit/gerrit-oauth-provider/tools/bzl/BUILD
new file mode 100644
index 0000000..c5ed0b7
--- /dev/null
+++ b/app/gerrit/gerrit-oauth-provider/tools/bzl/BUILD
@@ -0,0 +1 @@
+# Empty file required by Bazel