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ARROW-16324: [Go] Implement Dictionary Unification (#13529)

In addition to adding a `DictionaryUnifier` object, and functions for unifying Chunked arrays and Tables, this also adds the necessary SIMD implemented functions to perform the transposition of the integers (along with a benchmark). Calling `TransposeInts` on an array of 1000 8-bit integers across a 50 element mapping took only 30 ns on my laptop as opposed to around 7000 ns for non-SIMD solution. Pure-Go implementations are also provided for the processors that don't have SSE4 or AVX2 or for other architectures than amd64.

Authored-by: Matthew Topol <mtopol@factset.com>
Signed-off-by: Matthew Topol <mtopol@factset.com>