Split Rendering outstanding tasks

This issue is to track the remaining tasks related to split rendering:

• Split rendering support for remaining rendering paths:
  • Decoder:
    • ParamISM, MASA, McMASA, low-bitrate SBA tracked in #623 (closed) (dependent on #156 (closed))
      • → Draft MR: !856 (merged)
    • ParamMC, ParamUpmix
  • External Renderer:
    • MASA (dependent on #623 (closed), #156 (closed))
    • ParamBin+FastConv renderer support via CLDFB interface (#191 (closed), partially implemented)
• Addition of test cases for different split-codec configurations (currently only defaults are tested)
• Verification of Euler2Quat / Rotation matrix conversions and potential bug (see comment) --> @tamarapu
• Bitrate switching (decoder)
• Refactoring/removal of dependency on IVAS_RENDER_TYPE_OVERRIDE to e.g. SPLIT_BIN_RENDERER_SELECTION --> @tamarapu
• Code cleanup (TODOs and #if 0) and removal of accidental switch nesting
• formal improvements - see the list in !860 (merged)