Add Packard Bell Legend 300sx (port it from PCem)

[pankoza2-pl]

Is your feature request related to a problem? Please describe.
No, I just want the Packard Bell 300sx added

Describe the solution you'd like
Add the Packard Bell Legend 300sx 386sx machine, because PCem has that and 86Box doesn't, I think it should be easy to port it to 86Box

Additional context
BIOS ROM for Packard Bell Legend 300sx: https://github.com/BaRRaKudaRain/PCem-ROMs/tree/master/pb_l300sx

[OBattler]

Already requested here: #505 , so duplicate.

Also, PCem's emulation is incomplete - they do not emulate the UMC UM82C862F Super I/O chip.