Major state refactoring of pc98 based HW

[angelosa]

This is a first major step in splitting up machine classes in NEC PC98 family tree.

Highlights:

• Splits up derivative HWs into own state machine and files (pc98ha.cpp, pc9821.cpp and pc9801_epson.cpp);
• Adds a preliminary uPD4991a parallel RTC, used by pc98ha;
• Fix -26, -86, -118 C-bus sound board dips or jumper settings;
• Fix default sound card for pc9821 (-86) and pc9821ce2 / pc9821cx3 (-118);
• Adds preliminary MAD Factory Otomichan-kai C-bus sound board;
• Adds boilerplate code for C-bus installing board I/Os, avoiding the possible inconvenience of board(s) getting silently unmapped by other installed boards;
• Major refactoring of HW dip switches readouts, using required_ioports instead of scattering things around in PPI hooks;
• Extensive QA rundown, including research on missing features and undumped machines.

Addresses the following bugs:

• Don't passthrough mouse irq frequency when cycle setting is setup too, fixes jastrike mouse input on options menu;
• Fix kanji RAM window LR readback, makes telenetm to properly display 8x16 chars on RS and derivative machines;

New machines marked as NOT_WORKING

PC-98LT [anonymous]
PC-98HA "Handy98" [anonymous]
PC-9821Nr15 (98NOTE Lavie) [flyingharuka]
PC-9821Nr166 (98NOTE Lavie) [flyingharuka]
PC-9821Nw150 (98NOTE Lavie) [flyingharuka]
PC-9821Ra266 (98MATE R) [flyingharuka]
PC-9821Cx3 (98MULTi CanBe) [flyingharuka]
PC-9801VX [qazmko1029]
PC-9801US [CoolMod]

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pc8801.cpp: fixed OPNA RAM readback, allowing SWs to playback ADPCMs properly.

[cuavas]

Probably a good idea to run srcclean on the affected files to avoid more churn after merging – there are at least a few places with space indenting that will get hit.

[angelosa]

Looks like pc9821 "pegc" mode got regressed in 57e4628
Pretty sure I've tested panicbom just before merging to latest:

[angelosa]

I'm done here for the time being.