Harmonize function pair tcx_scalar_quantization_rateloop_fx() and function pair tcx_scalar_quantization_fx()

• It should be possible to harmonize functions tcx_scalar_quantization_rateloop_fx() and tcx_scalar_quantization_rateloop_ivas_fx().

1. First investigate if it's possible at all.
2. The resulting unified function must be named tcx_scalar_quantization_rateloop_fx() .

• Also The function tcx_scalar_quantization_fx() and tcx_scalar_quantization_ivas_fx() are closely related to the first function.

1. Harmonizing them should be possible.
2. If possible, they should be named function tcx_scalar_quantization_fx()