Support multiple nodes within one JVM using different directories

### Problem

The `@HapiTest` and `@HapiTestSuit` engine needs to add support for multiple nodes. Right now, each node uses directories for data and eventstreams. The platform code uses `FileUtils` in a static utility way that assumes it is using the current working directory. Instead, we need a non-final way to determine the "absolute" path.

### Solution

We could possibly move the getAbsolutePath methods from FileUtils to PathsConfig or other configs with paths as helper methods, and introduce a config property for the working directory for the node.

### Alternatives

_No response_