Replace `jboss.server.config.dir` with `kc.home.dir`

### Description

We should remove all references to `jboss.server.config.dir` and leverage `kc.home.dir` instead.

Should probably be `kc.home.dir/conf` as don't think there's a conf specific property.

### Discussion

_No response_

### Motivation

_No response_

### Details

_No response_