bsc: add TC_ho_neighbor_config_1 thru _7

Add tests to play through various neighbor configurations.
Tests will pass as soon as osmo-bsc I29bca59ab232eddc74e0d4698efb9c9992443983
is merged.

Add RSL2 to allow triggering handover to BTS 2.

Adjust osmo-bsc.cfg to match the new tests. Also applied in docker-playground
I1c57a04747f5ec004ccf4657954dcb0b003c24fc.
    - Actually enable handover.
    - Add bts 3

Depends: osmo-bsc I8623ab581639e9f8af6a9ff1eca990518d1b1211 ('no neighbors')
Related: OS#4056
Change-Id: Ia4ba0e75abd3d45a3422b2525e5f938cdc5a04cc
diff --git a/library/RSL_Emulation.ttcn b/library/RSL_Emulation.ttcn
index 790dd7a..309ec13 100644
--- a/library/RSL_Emulation.ttcn
+++ b/library/RSL_Emulation.ttcn
@@ -45,6 +45,8 @@
 	/* second BTS / DChan during hand-over */
 	port RSL_DCHAN_PT RSL1;
 	port RSLEM_PROC_PT RSL1_PROC;
+	port RSL_DCHAN_PT RSL2;
+	port RSLEM_PROC_PT RSL2_PROC;
 };
 
 type record RSLDC_ChanRqd {