use server hostname in sample client configs

This is a little more robust and a little more readable.

README.md

@@ -65,8 +65,8 @@ conversations:
   - group: "group1"
 
     # The <address>:<port> of the message server,
-    # where <address> is an IP or onion address.
-    server: "insert.ip.or.onion:6397"
+    # where <address> is an IP, onion address, or hostname.
+    server: "server.maybe.onion:6397"
 
     # The number of seconds to wait until the client starts sending messages.
     # This should be long enough that all clients have had time to start

shadow/client/shadow.data.template/hosts/client1/alice.yaml

@@ -1,7 +1,7 @@
 user: "Alice"
 conversations:
   - group: "group1"
-    server: "100.0.0.1:6397"
+    server: "server:6397"
     bootstrap: 5.0
     retry: 5.0
     distributions: &dists
@@ -13,7 +13,7 @@ conversations:
       a_s: { distribution: "Normal", mean: 10.0, std_dev: 5.0 }
       a_r: { distribution: "Normal", mean: 10.0, std_dev: 5.0 }
   - group: "group2"
-    server: "100.0.0.1:6397"
+    server: "server:6397"
     bootstrap: 5.0
     retry: 5.0
     distributions: *dists

shadow/client/shadow.data.template/hosts/client2/bob.yaml

@@ -1,7 +1,7 @@
 user: "Bob"
 conversations:
   - group: "group1"
-    server: "100.0.0.1:6397"
+    server: "server:6397"
     bootstrap: 5.0
     retry: 5.0
     distributions: &dists
@@ -13,7 +13,7 @@ conversations:
       a_s: { distribution: "Normal", mean: 10.0, std_dev: 5.0 }
       a_r: { distribution: "Normal", mean: 10.0, std_dev: 5.0 }
   - group: "group2"
-    server: "100.0.0.1:6397"
+    server: "server:6397"
     bootstrap: 5.0
     retry: 5.0
     distributions: *dists

shadow/client/shadow.data.template/hosts/client2/carol.yaml

@@ -1,7 +1,7 @@
 user: "Carol"
 conversations:
   - group: "group1"
-    server: "100.0.0.1:6397"
+    server: "server:6397"
     bootstrap: 5.0
     retry: 5.0
     distributions:

shadow/client/shadow.data.template/hosts/client3/dave.yaml

@@ -1,7 +1,7 @@
 user: "Dave"
 conversations:
   - group: "group2"
-    server: "100.0.0.1:6397"
+    server: "server:6397"
     bootstrap: 5.0
     retry: 5.0
     distributions: