Integrate marlin fp16/bf16-float8 matrix multiplication kernel

[dacorvo]

Since the introduction of mixed-precision fp16-int4 MARLIN (Mixed Auto-Regressive Linear) kernels by IST-DASLab, new mixed-precision MARLIN kernels have been introduced for other data types.

In particular, mixed-precision fp16/bf16-float8 kernels have been contributed to TGI and could be integrated in optimum-quanto as well with a companion FP8MarlinQBytesTensor to pack the weights.

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[dacorvo]

Done in #296