Add configuration option to make the HTTP management interface unavailable on non-master HCs

This is a sub-requirement of WFCORE-338 and shouldn't be included independent of that without prior discussion.

If a user has a group of candidate domain controllers, a classic way of providing a consistent URL for management clients in the face of changes in the elected DC is to front the set of candidates with a reverse proxy. But for that to work well, the proxy should only see one working HC at a time. For that to happen, we need the non-elected HCs to not open a listener on the HTTP management interface unless they are elected.

Since users may not want this behavior (e.g. if they don't have a reverse proxy set up and thus will get no benefit), this needs to be configurable.

Note that if users elect to use this function they will need to set up a native-management interface to handle the intra-domain traffic.

An open question is whether the interface should not be available at all or whether it should just be that certain contexts are not available.

Also worth some thought before proceeding with this is thinking about how a mod_cluster proxy would be integrated. Doing the mod_cluster integration is out of scope for this task, but it makes sense to think about it a bit so we don't go down a path that will make later mod_cluster work harder.