smalltown -> metropolis

This pass removes all mentions of Smalltown, both from code and comments,
and replaces them with appropriate new terminology.

Test Plan: Refactor, covered by CI.

X-Origin-Diff: phab/D674
GitOrigin-RevId: 04a94d44ef07d46f7821530da5614daefe16d7ea
diff --git a/metropolis/test/e2e/k8s_cts/main.go b/metropolis/test/e2e/k8s_cts/main.go
index 728a890..8ee63be 100644
--- a/metropolis/test/e2e/k8s_cts/main.go
+++ b/metropolis/test/e2e/k8s_cts/main.go
@@ -14,7 +14,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// This package launches a Smalltown Cluster with two nodes and spawns in the CTS container. Then it streams its output
+// This package launches a Metropolis cluster with two nodes and spawns in the CTS container. Then it streams its output
 // to the console. When the CTS has finished it exits with the appropriate error code.
 package main