Reduce binary size of refine functions

[tfeher]

The refine functions that work with GPU data use IVF-Flat under the hood to perform the refinement operation. This PR adds extern template declarations for ivfflat_interleaved_scan and uses these in the refine functions. This way we avoid recompiling the IVF-Flat search kernels, and save binary size.

[tfeher]

The ivfflat_interleaved_scan function is expected to be the largest contributor in binary size for the refine_device. We still have a few other kernel calls in refine_device, In a separate PR I will check if we can get rid of those.

[tfeher]

The binary size is nicely reduced, but test fail due to undefined symbols. It worked locally, I will look into it.

filname	compile time	binary size
refine_device_half_float.cu.o	112.149 s	2.185 MB
refine_device_float_float.cu.o	111.532 s	2.263 MB
refine_device_uint8_t_float.cu.o	111.155 s	2.183 MB
refine_device_int8_t_float.cu.o	110.015 s	2.183 MB

[tfeher]

The error is related to the filter type used for instantiating the search kernels. I am looking into the details.