Install experimental arm64 & arm32 powershell for Empire

Let's download and install the experimental arm packages manually before
installing Empire.

We also have to set the following environmental variable

POWERSHELL_TELEMETRY_OPTOUT=1

in "/etc/profile.d/powershell.sh" & "/etc/bash.bashrc" to opt out of
Microsofts telemetry program (DELETE_ME_TO_DISABLE_CONSOLEHOST_TELEMETRY
has been retired by MS)

nethunter-fs/stages/stage3

@@ -43,11 +43,46 @@ dpkg-divert --remove --rename /usr/sbin/invoke-rc.d
 EOF
 # End of third-stage script
 
+# Let's do a little bit of magic from outside the chroot
 if [ "$build_size" = full ]; then
 	# We should run git clone outside chroot because it has issues with machine-code translation
 	git clone https://github.com/Proxmark/proxmark3.git "$rootfs/opt/proxmark3"
 	git clone https://github.com/adaptivethreat/Empire.git "$rootfs/opt/Empire"
 
+	# powershell for arm64 is not yet available in Microsofts repos so let's install it manually
+	if [ $build_arch == "arm64" ]; then
+		mkdir -p $rootfs/opt/microsoft/powershell
+		wget -P $rootfs/opt/microsoft/powershell https://github.com/PowerShell/PowerShell/releases/download/v6.2.0-preview.4/powershell-6.2.0-preview.4-linux-arm64.tar.gz
+                tar -xzf $rootfs/opt/microsoft/powershell/powershell-6.2.0-preview.4-linux-arm64.tar.gz -C $rootfs/opt/microsoft/powershell
+		rm $rootfs/opt/microsoft/powershell/powershell-6.2.0-preview.4-linux-arm64.tar.gz
+	fi
+	if [ $build_arch == "armhf" ]; then
+		mkdir -p $rootfs/opt/microsoft/powershell
+		wget -P $rootfs/opt/microsoft/powershell https://github.com/PowerShell/PowerShell/releases/download/v6.2.0-preview.4/powershell-6.2.0-preview.4-linux-arm32.tar.gz
+                tar -xzf $rootfs/opt/microsoft/powershell/powershell-6.2.0-preview.4-linux-arm32.tar.gz -C $rootfs/opt/microsoft/powershell
+		rm $rootfs/opt/microsoft/powershell/powershell-6.2.0-preview.4-linux-arm32.tar.gz
+	fi
+	# Microsoft no longer supports deletion of the file DELETE_ME_TO_DISABLE_CONSOLEHOST_TELEMETRY to disable telemetry
+	# We have to set this environment variable instead
+	cat << EOF > "$rootfs/etc/profile.d/powershell.sh"
+# Microsoft no longer supports deletion of the file DELETE_ME_TO_DISABLE_CONSOLEHOST_TELEMETRY to disable telemetry
+# We have to set this environment variable instead
+
+export POWERSHELL_TELEMETRY_OPTOUT=1
+EOF
+
+        cat << EOF >> "$rootfs/etc/bash.bashrc"
+# Microsoft no longer supports deletion of the file DELETE_ME_TO_DISABLE_CONSOLEHOST_TELEMETRY to disable telemetry
+# We have to set this environment variable instead
+
+export POWERSHELL_TELEMETRY_OPTOUT=1
+EOF
+
+        # The installation of Empire will still throw a few errors in relation to not being able to install powershell and that it cannot disable telemetry but that is not
+	# to worry about anymore as we have taken care of it ourselves now
+
+# End of doing a little magic from outside the chroot
+
 	cat << EOF >> "$rootfs/third-stage"
 
 # Enable PHP in Apache
@@ -66,9 +101,9 @@ fi
 if cd /opt/Empire/setup; then
         # Lets patch install.sh to build xar for our target architecture
         if [ $build_arch == "arm64" ]; then
-            sed "install.sh" -i -e "s/(cd xar-1.5.2 \&\& \./configure)/(cd xar-1.5.2 \&\& \./configure --build=armv8l-unkown-linux-gnu)/"
+            sed "install.sh" -i -e "s/(cd xar-1.5.2 \&\& \.\/configure)/(cd xar-1.5.2 \&\& \.\/configure --build=armv8l-unkown-linux-gnu)/"
         elif [ $build_arch == "armhf" ]; then
-            sed "install.sh" -i -e "s/(cd xar-1.5.2 \&\& \./configure)/(cd xar-1.5.2 \&\& \./configure --build=armv7l-unkown-linux-gnu)/"
+            sed "install.sh" -i -e "s/(cd xar-1.5.2 \&\& \.\/configure)/(cd xar-1.5.2 \&\& \.\/configure --build=armv7l-unkown-linux-gnu)/"
         fi
 	chmod +x install.sh
 	printf "\n" | ./install.sh