AIXPB: add maxuproc to sys0 role

[aixtools]

Fixes: #3138

Checklist

• commit message has one of the standard prefixes
• faq.md updated if appropriate
• other documentation is changed or added (if applicable)
• playbook changes run through VPC or QPC (if you have access)
• VPC/QPC not applicable for this PR
• for inventory.yml changes, bastillion/nagios/jenkins updated accordingly

[github-actions]

A block has been put on this Pull Request as this repository is temporarily under a code freeze due to an ongoing release cycle.

If this pull request needs to be merged during the release cycle then please comment /merge and a PMC member will be able to remove the block.

If the code freeze is over you can remove this block by commenting /thaw.

[aixtools]

Is the freeze over?

[aixtools]

Again, is the freeze over? I was going to work further on some aixPB stuff, but don't want to have to be doing a lot of extra work because approved changes have not been merged yet. - i.e. I do not see my position to run the / thraw action.

UNLESS someone else says okay.

[karianna]

/thaw

[karianna]

Freeze is over as far as I'm aware.

Pull Request unblocked - code freeze is over.