cleanup of float struct members, replacing libcom functions in encoder with fxd

[x] Cleanup of structure members from ivas_stat_rend
[x] Cleanup of ivas_dirac_dec_binaural_render and ivas_omasa_dirac_td_binaural_jbm
[x] Cleanup of cy_auto_diff_smooth and cy_auto_diff_smooth_prev
[x] Integration of lib_com fixed functions in encoder
[x] dirac_output_synthesis_state_structure cleanup.

EVS 26.444 BE test passes.
pytests results: 597 failed, 381 skipped

MLD scores:
Original inputs:
MLD > 10: 67
MLD > 5 : 138
MLD < 5 : 392

+10dB inputs:
MLD > 10: 198
MLD > 5 : 195
MLD < 5 : 203

-10dB inputs:
MLD > 10: 23
MLD > 5 : 81
MLD < 5 : 493