rabbitmq charm causes non DISA-STIG compliance

[Jeff Hillman]

ubuntu 20.04.5
juju 2.9.37
charm latest/stable rev CH:123
rabbitmq-server 3.8.2
ussuri

When running `sudo usg fix disa_stig` against an ubuntu 20.04.5 machine, it becomes DISA-STIG compliant.

running `juju add-machine <user>@<ip>` and then `juju deploy rabbitmq-server --to 0` causes DISA-STIG to no longer be compliant

Specifically, running a diff against the compliant results `sudo usg audit disa_stig` and then against the newly deployed rabbitmq-server charm causes the following diff:

```
- <rule-result idref="file_groupownership_system_commands_dirs" time="2022-11-16T15:38:17" severity="medium" weight="1.
000000">
- <result>pass</result>
+ <rule-result idref="file_groupownership_system_commands_dirs" time="2022-11-18T17:37:34" severity="medium" weight="1.
000000">
+ <result>fail</result>
       <check system="http://oval.mitre.org/XMLSchema/oval-definitions-5">
         <check-content-ref name="oval:ssg-file_groupownership_system_commands_dirs:def:1" href="ssg-ubuntu2004-oval.xml"/>
       </check>
     </rule-result>

```

rabbitmq-server charm is breaking the file_groupownership_system_commands_dirs DISA-STIG compliance.

it looks like the charm is installing the lockfile-progs package, which is causing /usr/mail-* files to have a group ownership of mail instead of root.