[Linalg] Add a view type with base_view op

    This CL adds a linalg.view<?x?xf32> type and base_view op with the proper roundtripping test. The parser will be improved in a subsequent CL once portions of the mlir::Parser are exposed.

    For now this only supports dynamic views, static views will be introduced at a later time when they are needed.

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PiperOrigin-RevId: 244374180