We already have peer cells in the setup of generated enb/gnb, but there were no
X2/XN peers there. Add them to be able to see how handling of peers works.

Rendered files change as expected:

```
$ ./pythonwitheggs slapos-render-config.py && xdiff config/{old,out}
```

```diff
diff --git a/config/old/ors/enb/enb.cfg b/config/out/ors/enb/enb.cfg
index 252c2e379..15f3b68e9 100644
--- a/config/old/ors/enb/enb.cfg
+++ b/config/out/ors/enb/enb.cfg
@@ -22,7 +22,7 @@
     },
   ],
   gtp_addr: "127.0.1.1",
-  x2_peers: [],
+  x2_peers: ["44.1.1.1", "44.1.1.2"],
   enb_id: 0x1A2D0,

   // LTE cells
diff --git a/config/old/ors/gnb/enb.cfg b/config/out/ors/gnb/enb.cfg
index b401f3513..ac564db6c 100644
--- a/config/old/ors/gnb/enb.cfg
+++ b/config/out/ors/gnb/enb.cfg
@@ -22,7 +22,7 @@
     },
   ],
   gtp_addr: "127.0.1.1",
-  xn_peers: [],
+  xn_peers: ["55.1.1.1", "55.1.1.2"],
   gnb_id_bits: 28,
   gnb_id: 0x12345,
   en_dc_support: true,
```