[Improvement] Two classes of the same name

### What would you like to be improved?

We have two classes with the same name - this could be confusing:
./clients/client-java/src/main/java/com/datastrato/gravitino/client/FilesetCatalog.java
./api/src/main/java/com/datastrato/gravitino/file/FilesetCatalog.java

### How should we improve?

Rename one or more of the classes.

Start with the two named files: clients/client-java/src/main/java/com/datastrato/gravitino/client/FilesetCatalog.java and api/src/main/java/com/datastrato/gravitino/file/FilesetCatalog.java. Search for references to both classes and determine which names should change before updating usages. The work is done when the naming is unambiguous and the relevant Java build and tests pass.

Written by the indexing model from the issue text.