Add:http_response_class

[StefanAustin]

Need to add to the schema the http_response_class

Describe the log source:
All logs with an http_request_code

There are 5 groups/classes for http_response_codes
• "informational class" ( 100 – 199 )
• "successful response" ( 200 – 299 )
• "redirection messages" ( 300 – 399 )
• "client error" ( 400 – 499 )
• "server error" ( 500 – 599 )

I added a lookup in core to match these codes because for a dashboard they are very useful to monitor the health of a webserver.

[miwent]

s/b http_response_class