new "regexpi" filter for matching processes/services case insensitive

[lgmu]

for example: check_process "filter=exe regexp "WES.*"

-> in nsclient this is always case sensitive

Would be great to be able to do something like this: /wes.*/i or "regexpi"

For users I think "regexpi" would be easier to use :)

[sni]

both ways are possible now, see https://github.com/ConSol-Monitoring/snclient/blob/main/docs/filter/_index.md