Add check that filename begins with /hosthome

This ensures that the file can be store in the host ${HOME} dir
outside of the container.

Also added ${TANGO_CONTAINER_ENV} that sets environment variables

tools/ConfigDb/load_ConfigDb.sh

 if [ ${#} -ne 1 ]; then
     echo "You must provide a file name for the TANGO_HOST DB dump!"
     exit -1
+# Check if the filename begins with /hosthome:
+elif [ ${1##/hosthome/} != ${1//\/hosthome\//} ]; then
+    echo "You must provide a filename that begins with \"/hosthome/\".  Why is that?  Because the file needs to be stored from within the container to the hosts file system and your HOME directory will be mounted as /hosthome."
+    exit -2
 fi
-docker exec -it dsconfig json2tango --write ${1}
+docker exec -it ${TANGO_CONTAINER_ENV} dsconfig json2tango --write ${1}

tools/ConfigDb/update_ConfigDb.sh

 if [ ${#} -ne 1 ]; then
     echo "You must provide a file name for the TANGO_HOST DB dump!"
     exit -1
+# Check if the filename begins with /hosthome:
+elif [ ${1##/hosthome/} != ${1//\/hosthome\//} ]; then
+    echo "You must provide a filename that begins with \"/hosthome/\".  Why is that?  Because the file needs to be stored from within the container to the hosts file system and your HOME directory will be mounted as /hosthome."
+    exit -2
 fi
-docker exec -it dsconfig json2tango --update ${1}
+docker exec -it ${TANGO_CONTAINER_ENV} dsconfig json2tango --update ${1}