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ARROW-9287: [C++] Support unsigned dictionary indices

Summary of places where changes were needed:

* Add to integration tests. uint64 does not work in JavaScript so this is disabled temporarily (NEEDS TICKET)
* Support in DictionaryArray::GetValueIndex, Transpose, FromArrays
* Support in C interface implementation
* Support in IPC read/write
* Handle in `DictionaryScalar::GetEncodedValue`
* Relax checks in DictionaryType argument validation
* Add unsigned int support to internal::TransposeInts
* Support in Parquet direct dictionary encoding (`PutIndices`)

Converting to pandas from unsigned indices is disabled (raises exception). That turned out to be somewhat involved because of how nulls are handled (pandas only accepts signed integers), so think we should deal with this as follow up (NEEDS TICKET).

Closes #7659 from wesm/ARROW-9287

Authored-by: Wes McKinney <wesm@apache.org>
Signed-off-by: Wes McKinney <wesm@apache.org>