[Feature Request]Ability to convert MIDI playback to S98 format (MID2S98)

[freq-mod]

specs: https://vgmrips.net/wiki/S98_File_Format

Kinda inspired by #101, S98 file format supports completely arbitrary amount of chips of any type, just as much as library can handle (so, in theory, 100 of them!)

Both YM2608 and YM2612 are supported, also Mega Drive's SN PSG is supported.

[jpcima]

It's a feature worth considering. A problem, for time being, it's that there isn't a s98 optimizer available, which is extremely useful for reducing the data size. There exists a utility vgm_cmp in ValleyBell's vgmtools. One can port the tool directly; or decombine the S98 file into single chip VGMs, process individually, and recombine into S98.