README: Mark oFono backend as not actively developed

The ofono section was a bit too prominent in the README considering that it's
not actively developed.

The section was moved to its own file.

README.md

@@ -63,45 +63,6 @@ directory in the plugin search path. F.e.
 
 
 ### oFono
-There is also an oFono backend, "ofono".  This was the first backend
-developed but has been superceded by the ModemManager backend so it
-may suffer from a lack of attention.
 
-The ofono backend depends on oFono Modem objects being present on
-D-Bus.  To run oFono with useful output:
-
-    sudo OFONO_AT_DEBUG=1 ofonod -n -d
-
-The test programs within the [oFono source
-tree](https://git.kernel.org/pub/scm/network/ofono/ofono.git) are
-useful to bring up a modem to a suitable state.  For example:
-
-    cd $OFONO_SOURCE/test
-    ./list-modems
-    ./enable-modem /sim7100
-    ./online-modem /sim7100
-
-Then run Calls:
-
-    /usr/bin/gnome-calls -p ofono
-
-
-#### Phonesim
-One can also make use of the oFono modem simulator, phonesim (in the
-ofono-phonesim package in Debian):
-
-    ofono-phonesim -p 12345 -gui /usr/local/share/phonesim/default.xml
-
-then, ensuring /etc/ofono/phonesim.conf has appropriate contents like:
-
-    [phonesim]
-    Address=127.0.0.1
-    Port=12345
-
-run oFono as above, then:
-
-    cd $OFONO_SOURCE/test
-    ./enable-modem /phonesim
-    ./online-modem /phonesim
-
-And again run Calls.
+This plugin is not in active development anymore, so your mileage may vary.
+See [here](ofono.md) for more information.

ofono.md

@@ -0,0 +1,45 @@
+# oFono
+
+There is also an oFono backend, "ofono".  This was the first backend
+developed but has been superceded by the ModemManager backend so it
+may suffer from a lack of attention.
+
+The ofono backend depends on oFono Modem objects being present on
+D-Bus.  To run oFono with useful output:
+
+    sudo OFONO_AT_DEBUG=1 ofonod -n -d
+
+The test programs within the [oFono source
+tree](https://git.kernel.org/pub/scm/network/ofono/ofono.git) are
+useful to bring up a modem to a suitable state.  For example:
+
+    cd $OFONO_SOURCE/test
+    ./list-modems
+    ./enable-modem /sim7100
+    ./online-modem /sim7100
+
+Then run Calls:
+
+    /usr/bin/gnome-calls -p ofono
+
+
+## Phonesim
+
+One can also make use of the oFono modem simulator, phonesim (in the
+ofono-phonesim package in Debian):
+
+    ofono-phonesim -p 12345 -gui /usr/local/share/phonesim/default.xml
+
+then, ensuring /etc/ofono/phonesim.conf has appropriate contents like:
+
+    [phonesim]
+    Address=127.0.0.1
+    Port=12345
+
+run oFono as above, then:
+
+    cd $OFONO_SOURCE/test
+    ./enable-modem /phonesim
+    ./online-modem /phonesim
+
+And again run Calls.