//count command should respect block limits

### The Problem

Currently, the `//count` command does not respect block limits. This is fine for smaller counts, but executing the command over a very large region can create serious performance issues, and in some cases crash the server.

### A Solution

It would be nice if the `//count` command respected block limits imposed on other world edits.

### Alternatives

Currently, disabling access to the `//count` command is a workaround.

It could be possible to have a separate block limit for the //count command, but this may add extra complexity which is not needed.

### Anything Else?

Complex counts in particular can be extremely taxing.

For example `//count dirt` has less of a performance impact than `//count air,dirt,sand,water`.