NagiosCore 4 support

[T.J_Yang]

Hi

• WHAT: I am hoping to see check-mk-raw supports nagioscore 4.

• WHY:

  • nagios3 instances are less common, nagioscore 4 is mainstream now adays.
  • To attract more nagioscore 4 converts.

• Reference:

  • https://checkmk-en.mathias-kettner.narkive.com/cauX9A99/check-mk-english-nagios-version-included-in-check-mk-raw