root.sh: Generate more locales during install

As a guide we use the ones present in the welcome screen for now.

This helps libephonenumber to find the right locale, see:
Closes: Librem5/OS-issues#66

root.sh

@@ -221,7 +221,14 @@ function setup_sshd()
 
 function setup_locale()
 {
-    echo "en_US.UTF-8 UTF-8" > "${basedir}/etc/locale.gen"
+    cat <<EOF > "${basedir}/etc/locale.gen"
+ar_SA.UTF-8 UTF-8
+de_DE.UTF-8 UTF-8
+en_US.UTF-8 UTF-8
+es_ES.UTF-8 UTF-8
+fr_FR.UTF-8 UTF-8
+ru_RU.UTF-8 UTF-8
+EOF
     chroot "${basedir}" dpkg-reconfigure locales
 }