Adds open elevated folder to right-click menu

Adds ability to open file manager as an elevated user, by adding a PolKit
script for xdg-open  and integrating it into PCManFM's right-click context menu
after a user called for this [1].

[1] #281

src/livecd/chroot/usr/local/bin/xdg-open-pkexec

@@ -0,0 +1,2 @@
+#!/bin/sh
+pkexec "/usr/bin/xdg-open" "$@"

src/livecd/chroot/usr/local/share/file-manager/actions/open-root-file-manager.desktop

@@ -0,0 +1,10 @@
+[Desktop Entry]
+Type=Action
+Name=Open root file manager
+Profiles=profile-zero;
+Icon=system-file-manager
+
+[X-Action-Profile profile-zero]
+MimeTypes=inode/directory;
+Exec=/usr/local/bin/xdg-open-pkexec %f
+Name=Default profile

src/livecd/chroot/usr/share/polkit-1/actions/com.rescuezilla.xdg-open.policy

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE policyconfig PUBLIC "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/PolicyKit/1/policyconfig.dtd">
+<policyconfig>
+
+    <vendor>Rescuezilla</vendor>
+    <vendor_url>https://rescuezilla.com/</vendor_url>
+    <icon_name>xdg-open</icon_name>
+    <action id="com.rescuezilla.xdg-open">
+
+        <description gettext-domain="rescuezilla">Run xdg-open as root</description>
+        <message gettext-domain="rescuezilla">Authentication is required to run xdg-open as root</message>
+        <defaults>
+            <allow_any>auth_admin</allow_any>
+            <allow_inactive>auth_admin</allow_inactive>
+            <allow_active>auth_admin</allow_active>
+        </defaults>
+        <annotate key="org.freedesktop.policykit.exec.path">/usr/bin/xdg-open</annotate>
+        <annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>
+
+    </action>
+
+</policyconfig>