Confusing naming of unrelated concepts: `EnsoFile` and `Enso_File`. We should rename at least one of these.

[radeusgd]

This is a minor problem, but I think worth adressing.

Currently we have two files that are named very similarly, but are different things, which may cause some confusion.

There is:

• Enso_File.enso which is an Enso type for remote files stored in the Enso Cloud,
• EnsoFile.java which is the implementation of builtin methods on the Enso File type (declared in File.enso).

The naming is misleading because it sounds like EnsoFile.java may have something to do with Enso_File.enso whereas it actually concerns File.enso.

[radeusgd]

We could consider renaming Enso_File to Cloud_File, but that may be too generic. Enso_Cloud_File will probably be too long a name for a public API.

Alternatively, EnsoFile.java is only part of private API - an implementation detail - so it may be easiest to rename that one - e.g. into FileBuiltins.java or BuiltinFile.java or something like that.