Consider allowing @NamedEntityGraph at the method level

I would love to be able to write a Jakarta Data repository method like this:

```java
@Find
@NamedEntityGraph(attributeNodes =
{@NamedAttributeNode(Author_.ADDRESS),
@NamedAttributeNode(Author_.BOOKS)})
Author author(String ssn);
```

But this doesn't work right now, because `NamedEntityGraph` is constrained to `@Target({TYPE})`.

I think we should consider relaxing that constraint to allow `@NamedEntityGraph` in other locations (e.g. package descriptors and methods).

An objection to this proposal could be that `NamedEntityGraph` is a bad name for this usage pattern, and that the annotation is generally quite verbose.

@njr-11

Start by reviewing the declaration and current uses of Jakarta Data's @NamedEntityGraph, especially its @Target({TYPE}) constraint and the repository method example. Determine whether method and package-descriptor placement should be supported, and document how the annotation name and verbosity affect the proposed API. Done means the scope and API direction are agreed.

Written by the indexing model from the issue text.