docs: add HTTPS healthcheck option (#4102)
docs: add HTTPS healthcheck option (#4102)

Add documentation for HTTPS healthcheck option with a note regarding SSL certificate validation.
janisz/marathon,janisz/marathon,gsantovena/marathon,mesosphere/marathon,meln1k/marathon,timcharper/marathon,mesosphere/marathon,janisz/marathon,meln1k/marathon,natemurthy/marathon,meln1k/marathon,meln1k/marathon,natemurthy/marathon,gsantovena/marathon,guenter/marathon,gsantovena/marathon,mesosphere/marathon,timcharper/marathon,Caerostris/marathon,janisz/marathon,guenter/marathon,Caerostris/marathon,Caerostris/marathon,timcharper/marathon,meln1k/marathon,guenter/marathon,janisz/marathon,guenter/marathon,Caerostris/marathon,mesosphere/marathon,Caerostris/marathon,mesosphere/marathon,guenter/marathon,gsantovena/marathon,gsantovena/marathon,natemurthy/marathon