`PartialOrd` for structs with incomparable fields

### Is your feature request related to a problem or challenge?

> What requires this manual derivation? Is it some other extension trait would need to also require `PartialOrd`?
>
> I am thinking it would be really nice to file a ticket tracking what it would take to use a derived `PartialOrd` to make this code more maintainable

_Originally posted by @alamb in https://github.com/apache/datafusion/pull/12481#discussion_r1761693610_

#12481 gives a possible implementation for PartialOrd, using a mix of manual implementations and derivations. The main blocker on using only derivations is `DFSchemaRef`, which is an incomparable type, along with the associated `Schema`, and minorly `HashMap`.

### Describe the solution you'd like

There are a couple of possible solutions. One simple one might be to just give a manual implementation of `PartialOrd` for `DFSchemaRef` that just returns `None`, allowing for types using it to derive `PartialOrd`. However, this would still leave a gap for the other datatypes used.

### Describe alternatives you've considered

Another solution would be to use something like the [derivative](https://crates.io/crates/derivative) crate, but that means another attribute for the struct, and additional attributes for the fields being excluded.

The current alternate solution being used for structs with >3 fields in #12481 is to have a inner struct for the `PartialOrd` manual implementation, that excludes in incomparable fields. This is easier to maintain, but also has a few drawbacks.

### Additional context

Relevant: #8932.

Start by reviewing PR #12481 and the existing PartialOrd implementations involving DFSchemaRef, Schema, and HashMap; issue #8932 provides additional context. Determine which incomparable fields and struct patterns the project needs to support, then define and validate an agreed approach for maintainable derived or manual ordering.

Written by the indexing model from the issue text.