client: docker: add exec wrapper, update completion

client/src/docker/lib/internal/lib_docker.bash

@@ -505,6 +505,11 @@ function lib_docker::__shell()
   docker exec -it --user "$global_arg_user" --workdir / "$global_container" /bin/bash
 }
 
+function lib_docker::__exec()
+{
+  docker exec -it "$global_container" /bin/bash -i -c "$@"
+}
+
 function lib_docker::__parse_args_edit()
 {
   [ -z "$global_usage" ] && lib_utils::die_fatal

client/src/docker/lib/lib_docker.bash

@@ -218,6 +218,16 @@ function lib_docker::shell()
   lib_utils::catch $?
 }
 
+#
+# Execute command within a running docker-finance container
+#
+
+function lib_docker::exec()
+{
+  lib_docker::__exec "$@"
+  lib_utils::catch $?
+}
+
 #
 # Edit client configuration of given docker-finance instance
 #