Disable the screensaver on macOS definitely and permanently

Change-Id: I8856eebfe91b9e1cc2cc318a1e7ea80348f1486e
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@qt.io>

coin/provisioning/qtci-osx-10.10-x86_64/002-disable-screensaver.sh

+#!/bin/sh
+
+defaults -currentHost write com.apple.screensaver idleTime 0

coin/provisioning/qtci-osx-10.11-x86_64/002-disable-screensaver.sh

+#!/bin/sh
+
+defaults -currentHost write com.apple.screensaver idleTime 0

coin/provisioning/qtci-osx-10.8-x86_64/002-disable-screensaver.sh

+#!/bin/sh
+
+defaults -currentHost write com.apple.screensaver idleTime 0

coin/provisioning/qtci-osx-10.9-x86_64/002-disable-screensaver.sh

+#!/bin/sh
+
+defaults -currentHost write com.apple.screensaver idleTime 0