MC param, MC-paramupmix, few functions in qmetadata_encode converted and integrated

[x] ivas_core_pre_proc_front and pre_proc_ivas cleanup
[x] conversion and integeration changes for ivas_omasa_param_est_enc_fx
[x] calc_var_azi integration in ivas_qmetadata_entropy_encode_dir
[x] ivas_param_mc_param_est_enc, mc_paramupmix_enc path completion
[x] qmetadata_encode: (ivas_qmetadata_quantize_coherence_fx)