[C++] Implement basic functionality for new Binary/Utf8View types

PR https://github.com/apache/arrow/pull/37792 added a basic implementation of the new BinaryView and Utf8View (StringView) format additions. This included mostly just the basic objects (Array, DataType, Builder) and IPC support.
For being able to handle input that uses those new formats, there are some additional features we will have to support (eg receiving a dataset, doing some filtering/projection, and then converting to standard string type).

- [x] Array equality (included in initial implementation)
- [ ] also expose this as the "equal" kernel
- [x] Conversion (cast) to/from the standard binary and string types: https://github.com/apache/arrow/pull/43302
- [ ] Take / filter
- [ ] https://github.com/apache/arrow/issues/43010
- [x] Unique / dictionary encoding (included in initial implementation)