Ambisonics EVS Reference Conditions: Add option to process FOA only

According to the IVAS-4 Performance Requirements (https://www.3gpp.org/ftp/TSG_SA/WG4_CODEC/IVAS_Permanent_Documents/IVAS-3_S4-230368.zip, Section 4.2), the EVS reference conditions are

• 3x EVS (planar FOA)
• 4x EVS (FOA) If the input is e.g. HOA3, we compare IVAS at HOA3 vs. EVS at (planar) FOA.

Afaik, it's currently not possible to configure the EVS reference conditions to such a subset of the input format or IVAS conditions only. From what I can see is that EVS is applied on the same order as the input format. It would be good introduce an additional option per condition, to set the processed Ambisonics order to

• planarFOA
• FOA
• HOA2
• HOA3 If the specified Ambisonics order exceeds the input format, I would just abort with an error.

I'm attaching my test config as basis for further experimentation: test.yml