Prompt message to let the user know what will be installed

Change-Id: If9e0bc0a976c7a7ad035c5b0211efffd94e46b16
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>

installers/full_install_osm.sh

@@ -719,6 +719,7 @@ function deploy_perfmon() {
 
 function install_lightweight() {
     [ "$USER" == "root" ] && FATAL "You are running the installer as root. The installer is prepared to be executed as a normal user with sudo privileges."
+    [ -z "$ASSUME_YES" ] && ! ask_user "The installation will configure LXD, install juju, install docker CE and init a docker swarm, as pre-requirements. Do you want to proceed (Y/n)? " y && echo "Cancelled!" && exit 1
     echo "Installing lightweight build of OSM"
     LWTEMPDIR="$(mktemp -d -q --tmpdir "installosmlight.XXXXXX")"
     trap 'rm -rf "${LWTEMPDIR}"' EXIT