devtools/gerrit: attempt to deploy theme

This doesn't entirely work, as we need to use PolyGerrit 3 compatible
theme injection.

Change-Id: I13305a4774028bdb92c1449ddb461b59ce8ae82f
diff --git a/devtools/gerrit/theme/etc/GerritSite.css b/devtools/gerrit/theme/etc/GerritSite.css
new file mode 100644
index 0000000..97074f2
--- /dev/null
+++ b/devtools/gerrit/theme/etc/GerritSite.css
@@ -0,0 +1,7 @@
+html {
+    --header-background-color: #347dbe;
+    --header-text-color: #fff;
+    --header-title-content: "Gerrit";
+    --header-icon: url('/static/pepper-icon.png');
+    --header-icon-size: 1em;
+}