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_jb
[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