Factor out Substrait consumers into separate files

[gabotechs]

Which issue does this PR close?

• Closes [substrait] refactor consumer.rs #13864.

Rationale for this change

The consumer.rs file grew a bit too big (~3400 LOC). Good thing is that it's easily splittable into separate files, each one responsible for converting one Substrait node into one DataFusion Logical plan node. With this change, people can just go to the file that they care about greatly reducing the amount of information that they need to deal with.

What changes are included in this PR?

A refactor of Substrait consumer.rs file into multiple files following these rules:

• Every from_* prefixed function responsible for converting one Substrait node into one DataFusion Logical plan node is now factored out into its own file named after the original Substrait node (e.g. cast.rs, literal.rs, aggregate_rel.rs)
• Every helper function that was only used once for a specific node conversion is moved to the same file that holds the node conversion function
• Every helper function that is used by two or more node conversion functions is moved to a utils.rs file
• The visibility rules of the functions to the outside is left intact (with a small exception, see below), making proper use of pub(super) for functions that now need to be shared across different files.
• All the function names and function bodies are copy-pasted exactly as they were

There's one subtle public API change that might be nice to keep:

$ cargo public-api diff

Removed items from the public API
=================================
(none)

Changed items in the public API
===============================
(none)

Added items to the public API
=============================
+pub fn datafusion_substrait::logical_plan::consumer::from_substrait_type

That one should probably have been public from the beginning, and not exposing it now gets a bit messy as it's used outside of the consume module in the producer.rs tests, and hiding it to the outside would require introducing some #[cfg(test)] to the module definitions. I can hide though if people one a perfect no-api-change refactor.

Are these changes tested?

yes, by current pipelines.

Are there any user-facing changes?

The from_substrait_type function is now exposed