Support for reading a local path-based iceberg catalog

[samirsatpathy]

I created a local iceberg catalog on my disk using Spark. Is it possible to read it using the catalog directory path in iceberg-cpp? It looks like only rest endpoint catalog is supported.

[wgtmac]

While we don't have a filesystem based catalog implementation yet, we can use InMemoryCatalog to play with it for now. See https://github.com/apache/iceberg-cpp/blob/main/example/demo_example.cc for example.

[samirsatpathy]

How about hadoop catalog to read directly from an object store metadata url? Or is only rest catalog supported right now?

[wgtmac]

Hadoop catalog is not planned yet but welcome to contribution. Rest catalog client just gets started and I think it is our main focus at this moment.