add handover_2G suite, with handover.py test

Via VTY, handover two lchans of a voice call from bts0 to bts1 and back.

New scenarios/bts1-* allow selecting various types for bts1,
complementing the already existing files for selecting bts0.

Change-Id: I0b2671304165a1aaae2b386af46fbd8b098e3bd8
diff --git a/sysmocom/suites/handover_2G/suite.conf b/sysmocom/suites/handover_2G/suite.conf
new file mode 100644
index 0000000..00d3fca
--- /dev/null
+++ b/sysmocom/suites/handover_2G/suite.conf
@@ -0,0 +1,9 @@
+resources:
+  ip_address:
+  - times: 6 # msc, bsc, hlr, stp, mgw*2
+  bts:
+  - times: 2
+  modem:
+  - times: 2
+    features:
+    - voice