Allow to set file permission on haproxy.log file

[bmm-alc]

Description

The patch allows to define the permissions when rsyslog writes the log file.
I use it on a copy of the repo for years and forgot to submit it.

Related Issue

need to allow other tooling to read the file (ex: promtail)
perhaps that would be better to set permissions to 0600

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist:

• I have read the CONTRIBUTING document.
• I have run the pre-merge tests locally and they pass.
• I have updated the documentation accordingly. (I did not find a documentation file to update)
• I have added tests to cover my changes.
• All new and existing tests passed.

[bmm-alc]

Thanks for merging this, do you plan a release in a short time, so I can ditch my copy ? :)

[bmm-alc]

actuallyou did a release, thanks :)