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ARROW-10164: [Rust] Add support for DictionaryArray to cast kernel

This PR adds support to the rust compute kernel casting `DictionaryArray` to/from  `PrimitiveArray`/`StringArray`

It does not include full support for other types such as `LargeString` or `Binary` (though the code could be extended fairly easily following the same pattern). However, my usecase doesn't need `LargeString` or `Binary` so I am trying to get the support I need in rather than fully flesh out the library

Closes #8346 from alamb/alamb/ARROW-10164-dictionary-casts-2

Authored-by: alamb <andrew@nerdnetworks.org>
Signed-off-by: Andy Grove <andygrove@nvidia.com>