add example installer script

example_config/scripts/installer.sh

@@ -0,0 +1,32 @@
+#! /bin/sh
+
+# This is an example installer script. For OS-Installer to use it, place it at:
+# /etc/os-installer/scripts/installer.sh
+# The script gets called with the following environment variables set:
+# OSI_LOCALE             : Locale to be used in the new system
+# OSI_DEVICE_PATH        : Device path at which to install
+# OSI_DEVICE_IS_PARTITON : 1 if the specified device is a partition (0 -> disk)
+# OSI_USE_ENCRYPTION     : 1 if the installation is to be encrypted
+# OSI_ENCRYPTION_PIN     : The encryption pin to use (if encryption is set)
+
+if [ -z ${OSI_DEVICE_PATH+x} ]
+then
+    echo "Installer script called without all environment variables set!"
+    exit 1
+fi
+
+echo 'Installation started'
+
+# Pretending to do something
+echo 'Pretending to do something'
+
+for i in {1..20}
+do
+    sleep 0.1
+    echo -n '.'
+done
+
+echo
+echo 'Installation completed!'
+
+exit 0