New DoS: too much data in MapServer

[juagargi]

A new attack surface appears with the MapServer. If a malicious CA creates an absurd number of entries for a domain name, those will be recorded by the CT Log Server, and afterwards by the MapServer.
A client requesting the material for that domain name will receive as much data as the attacker decides, rendering the connection to the MapServer useless.

• Decide what attacker models appear because of this.
• Decide how to solve or mitigate this.