In order to ensure that connections via the maintenance port are not rejected during a connection storm, we do not want normal connections count reaching the limit to cause rejections of ops on the maintenance port. However, it is also not safe to indefinitely accept maintenance connections without any limit (since this could crash the system if there are way too many connections).

In this ticket, we should provide a separate limit for connections via the maintenance port. This could either look similar to the handling for exemptions to the max connection limit where we use a reserved executor whose thread number is limiter or it could look like a separate counter of connections with a certain set of the max connections reserved for those connections.