Update logcheck rules for latest debian defaults

Update logcheck rules (and add autopkgtest)

• Includes autopkgtests as discussed at https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1038163
• supercedes/incorporates both !6 (closed) and !5 (closed)

The rules are, i think ready, but adding autopkgtests i have hit an oddity on which i would like advice: the only way i could think of to test is to

• start rsyslog
• collect the log messages produced by rsyslog
• run logcheck
• expect that there should be no output: the logcheck rules should filter all log messages: if something is reported by logcheck then the logcheck rules need updating

This works as expected when i run the test by hand in a systemd-nspawn container.

but when running in the salsa pipeline starting rsyslog generates many log lines saying omysql has failed. These look like this:

2023-06-20T17:00:36.146645+00:00 ci-171-0e5c7180 rsyslogd: action 'action-0-ommysql' suspended (module 'ommysql'), retry 5. There should be messages before this one giving the reason for suspension. [v8.2304.0 try https://www.rsyslog.com/e/2007 ]

Are these

• indicating a bug? (i guess not - i dont understand what they are saying though)
• an oddity of running rsyslog in a salsa pipeline --- is there some setting i need to do within the test to disable mysql? (the '2007' page suggests this but i dont understand it. )
• genuine messages that rsyslog produces, and which logcheck should filter? (ive never seen them, but have only checked on bookworm and bullseye)
• does it matter that i didnt ask the test to run with isolation-container or isolation-machine?

Full output is eg https://salsa.debian.org/rpil2/rsyslog/-/jobs/4344011