playbook: Fix missing permission for slapuser

In the Wendelin learning track this permission is granted to the user via
"chgrp SLAPUSER /dev/i2c-3". Because we don't know the particular
slapuser we have to add the permission to all users of the slapsoft
group. Because /sys/bus/i2c/devices/i2c-3 is a virtual directory and
we want to make sure that even after rebooting or unplugging /
replugging of the sensor the permission is still granted udev rules
have been added.

playbook/roles/olimex-sensor/files/60-i2c-tools.rules

+SUBSYSTEM=="i2c-dev", KERNEL=="i2c-3", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:slapsoft /sys/bus/i2c/devices/i2c-3 ; chmod 640 /sys/bus/i2c/devices/i2c-3"

playbook/roles/olimex-sensor/tasks/main.yml

@@ -26,3 +26,9 @@
   template:
     src: read_bme280.j2
     dest: /usr/local/bin/read_bme280.py
+
+- name: Add access sensor permission for slapsoft
+  copy:
+    src: 60-i2c-tools.rules
+    dest: /etc/udev/rules.d/60-i2c-tools.rules
+    owner: root