Add chart to response codes that shows requests and response codes

[rschwietzke]

Compose a new chart that will be part of the network page to list all response codes (ordered from 0 to ..., but only the codes we have truly seen).

We will color the codes by range aka 0 to 99, 100 to 199, 200 to 299, and so on, so that one can easily see in what range that was.

• 1xx informational response – the request was received, continuing process
• 2xx successful – the request was successfully received, understood, and accepted
• 3xx redirection – further action needs to be taken in order to complete the request
• 4xx client error – the request contains bad syntax or cannot be fulfilled
• 5xx server error – the server failed to fulfil an apparently valid request

I imagine a chart that is similar to this, but a) colored differently, b) more compact aka not just single charts stacked.