Fixed job delete logic to cover RHEL6, CentOS6, *BSD and Solaris

[saito-hideki]

SUMMARY

• at -r command-line option does not work on RHEL6 and CentOS6. Therefore, we will need to modify delete logic to use atrm command instead of at -r.
• Fixed search logic for job_id to perform correctly on *BSD and Solaris.

ISSUE TYPE

• Bugfix Pull Request
• Fixes Fix: Resolve CI checks fail - Module at add chdir(#102) #218 (CI tests issue with CentOS6)

COMPONENT NAME

• ansible.posix.at

ADDITIONAL INFORMATION

• RHEL6 and CentOS6 does not have at -r option:

$ cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 6.10 (Santiago)
$ at -r
at: invalid option -- 'r'
Usage: at [-V] [-q x] [-f file] [-mMlbv] timespec ...
       at [-V] [-q x] [-f file] [-mMlbv] -t time
       at -c job ...
       atq [-V] [-q x]
       at [ -rd ] job ...
       atrm [-V] job ...
       batch

• The order of the job id number in the output column of atq on FreeBSD are different from Linux. We need to take care of the difference of job id position.

FreeBSD and NetBSD: job id is located at the end of the columns.
~~~
Date				Owner		Queue	Job#
Wed Dec 31 00:00:00 UTC 2200	root            c	9
~~~

OpenBSD: job id is located in the middle of the columns.
~~~
   Rank     Execution Date     Owner          Job       Queue
  1st   Jan  1, 2022 00:00   root       1640962800.c   c
~~~

Solaris: job id is located in the middle of the columns
~~~
 Rank     Execution Date     Owner      Job            Queue   Job Name
  1st   Jan  1, 2022 00:00   root       1640962800.a     a     stdin
~~~

Linux: job id is located at the beginning of the columns.
~~~
26	2022-01-01 00:00 a root
~~~

• at -c is different behavior on Solaris. So we need to read /var/spool/cron/atjobs/<job_id> to confirm the job details instead of at -c on Solaris nodes.

[saito-hideki]

It seems necessary to consider the behavior of get_matching_jobs() for Solaris. Therefore, I'll revert this PR to WIP.
https://github.com/ansible-collections/ansible.posix/blob/main/plugins/modules/at.py#L99

=> Fixed and waiting for the code review.

[saito-hideki]

Closing and re-opening for CI trigger.

[saito-hideki]

@Akasurde is there any chance to review this PR? I don't know how many use cases there are in CentOS 6, but I think it's good that delete logic works properly :)