Description of problem:

In lib389/tasks.py, there is a timeout of 120 * 2 seconds ( 4 minutes ) when a new task is created.
In case the task takes longer, dsconf returns the following message:

==========================================
...
DEBUG: The backup create task has failed with the error code: (None)
Traceback (most recent call last):
  File "/usr/sbin/dsconf", line 134, in <module>
    result = args.func(inst, None, log, args)
  File "/usr/lib/python3.6/site-packages/lib389/cli_conf/backup.py", line 20, in backup_create
    raise ValueError("The backup create task has failed with the error code: ({})".format(result))
ValueError: The backup create task has failed with the error code: (None)
ERROR: Error: The backup create task has failed with the error code: (None)
==========================================

It would be nice to:
* allow dsconf to specify a timeout ( maybe this is already possible but I don't see any documented option )
* provide additional information stating that the timeout was over.


Version-Release number of selected component (if applicable):

$ cat /etc/redhat-release
Red Hat Enterprise Linux release 8.4 (Ootpa)
$
$ rpm -qa | grep 389-ds-base
389-ds-base-debugsource-1.4.3.13-1.module+el8dsrv+8334+69a46a2e.x86_64
389-ds-base-libs-1.4.3.22-1.module+el8dsrv+10501+8ce33e95.x86_64
389-ds-base-debuginfo-1.4.3.13-1.module+el8dsrv+8334+69a46a2e.x86_64
389-ds-base-1.4.3.22-1.module+el8dsrv+10501+8ce33e95.x86_64
$

How reproducible:
Always.

Steps to Reproduce:
1. Launch a task that will last longer than 4 minutes.
2. Check the output of the dsconf command
3. Check the errors log

Actual results:
The dsconf command fails and returns no reason for the failure.

Expected results:
* Allow to specify the timeout
* Provide additional information about the failure.

Additional info:
Issue was seen at a customer site.
I could reproduce by reducing the timeout value in /usr/lib/python3.6/site-packages/lib389/tasks.py in the wait() function.

$ dsconf -v -D "cn=Directory Manager" ldap://localhost:5389 backup create
...
DEBUG: cn=backup_2021-08-11T17:49:34.483894,cn=backup,cn=tasks,cn=config getVal('nsTaskExitCode')
DEBUG: cn=backup_2021-08-11T17:49:34.483894,cn=backup,cn=tasks,cn=config getVal('nsTaskLog')
DEBUG: cn=backup_2021-08-11T17:49:34.483894,cn=backup,cn=tasks,cn=config getVal('nsTaskWarning')
DEBUG: cn=backup_2021-08-11T17:49:34.483894,cn=backup,cn=tasks,cn=config getVal('nsTaskExitCode')
DEBUG: cn=backup_2021-08-11T17:49:34.483894,cn=backup,cn=tasks,cn=config getVal('nsTaskLog')
DEBUG: cn=backup_2021-08-11T17:49:34.483894,cn=backup,cn=tasks,cn=config getVal('nsTaskWarning')
DEBUG: The backup create task has failed with the error code: (None)
Traceback (most recent call last):
  File "/usr/sbin/dsconf", line 134, in <module>
    result = args.func(inst, None, log, args)
  File "/usr/lib/python3.6/site-packages/lib389/cli_conf/backup.py", line 20, in backup_create
    raise ValueError("The backup create task has failed with the error code: ({})".format(result))
ValueError: The backup create task has failed with the error code: (None)
ERROR: Error: The backup create task has failed with the error code: (None)
$