Introduce doc/examples/ directory

It contains simple usual setups to get started with osmo-gsm-tester,
such as creating a 4G network using srsLTE or a 2G network using the
osmocom stack (+ ofono modems).

Change-Id: I55d5b1152da201799af21a77ef6c562f97bd94fc
diff --git a/doc/examples/2g_osmocom/defaults.conf b/doc/examples/2g_osmocom/defaults.conf
new file mode 100644
index 0000000..06d596a
--- /dev/null
+++ b/doc/examples/2g_osmocom/defaults.conf
@@ -0,0 +1,63 @@
+bsc:
+  net:
+    mcc: 901
+    mnc: 70
+    short_name: osmo-gsm-tester-msc
+    long_name: osmo-gsm-tester-msc
+    encryption: a5_0
+    codec_list:
+    - fr1
+
+msc:
+  net:
+    mcc: 901
+    mnc: 70
+    short_name: osmo-gsm-tester-msc
+    long_name: osmo-gsm-tester-msc
+    encryption: a5_0
+    authentication: optional
+
+bsc_bts:
+  base_station_id_code: 63
+  stream_id: 255
+  osmobsc_bts_type: sysmobts
+  channel_allocator: ascending
+  gprs_mode: gprs
+  num_trx: 1
+  max_trx: 1
+  trx_list:
+  - nominal_power: 23
+    max_power_red: 0
+    arfcn: 868
+    timeslot_list:
+    - phys_chan_config: CCCH+SDCCH4
+    - phys_chan_config: SDCCH8
+    - phys_chan_config: TCH/F
+    - phys_chan_config: TCH/F
+    - phys_chan_config: TCH/F
+    - phys_chan_config: TCH/F
+    - phys_chan_config: PDCH
+    - phys_chan_config: PDCH
+  - nominal_power: 23
+    max_power_red: 0
+    arfcn: 872
+    timeslot_list:
+    - phys_chan_config: TCH/F
+    - phys_chan_config: SDCCH8
+    - phys_chan_config: TCH/F
+    - phys_chan_config: TCH/F
+    - phys_chan_config: TCH/F
+    - phys_chan_config: TCH/F
+    - phys_chan_config: PDCH
+    - phys_chan_config: PDCH
+
+osmo_bts_trx:
+  max_trx: 2
+
+osmo_trx:
+  type: uhd
+  launch_trx: true
+  clock_reference: internal
+
+iperf3cli:
+  time: 60