Fix prerequisites in cephadm-preflight

[droidben]

I noticed that clients configured with cephadm-preflight.yml were not getting prerequisite packages installed. This was due to a wrong conditional in the playbook.

Also lvm2 is an official prerequisite as per the docs so I added it to the infra packages in the defaults as not all distros in all feature-flavors come with it installed.

[droidben]

I misinterpreted the clients group and what its purpose was supposed to be, hence my latest commit. But there is still the problem, that the clients group is left untouched by the preflight playbook. This is also fixed my this PR.

If you are still unsure as to what this is supposed to accomplish, here a comparison in playbook runs. Here rocky9-01 is admin, but not client and osd. The rest (02-04) is admin, client and osd.

existing prefligt playbook

TASK [install prerequisites packages on servers]
ok: [rocky9-01.testcluster.local]                     
changed: [rocky9-03.testcluster.local]                
changed: [rocky9-02.testcluster.local]                
changed: [rocky9-04.testcluster.local]                
                                                
TASK [install prerequisites packages on clients]
skipping: [rocky9-01.testcluster.local]               
skipping: [rocky9-02.testcluster.local]               
skipping: [rocky9-03.testcluster.local]               
skipping: [rocky9-04.testcluster.local]                  

As you can see, the clients are skipped, no packages are installed.

proposed preflight playbook

TASK [install prerequisites packages on servers]
changed: [rocky9-04.testcluster.local]                
changed: [rocky9-03.testcluster.local]                
changed: [rocky9-01.testcluster.local]                
changed: [rocky9-02.testcluster.local]                
                                                
TASK [install prerequisites packages on clients]
skipping: [rocky9-01.testcluster.local]               
ok: [rocky9-04.testcluster.local]                     
ok: [rocky9-02.testcluster.local]                     
ok: [rocky9-03.testcluster.local]                     

The clients are now not immediately skipped anymore and the required packages are installed.

[droidben]

Requesting @asm0deuz for review.

[asm0deuz]

jenkins test el8-functional

[asm0deuz]

jenkins test el9-functional

[asm0deuz]

@droidben It looks good to me but you need to squash your commits into one (now there are 5 commits)