client/container: implement debug log-levels

DOCKER_FINANCE_DEBUG will now support the following:

0 = no debug output
1 = `print_debug` (bash/PHP)
2 = level 1 + `set -xv` (bash)

container/src/finance/completion.bash

@@ -18,7 +18,7 @@
 # along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 # shellcheck disable=SC2154
-[ "$DOCKER_FINANCE_DEBUG" == true ] && set -xv
+[ "$DOCKER_FINANCE_DEBUG" == 2 ] && set -xv
 
 [ -z "$DOCKER_FINANCE_CONTAINER_FLOW" ] && exit 1