Allowing Config class to resolve isFullscreen flag from CLI arguments

[robyn-dressler]

Addresses feature request #1147

Changes:

• Move CLI argument parsing to Config class
• Added -f and --fullscreen flags that override isFullscreen in the config
• Added patchFile member variable to config (but excluding from TOML file, since it's game specific)
• Added second overload to Emulator::Run

I have unfortunately not been able to properly test fullscreen in my environment due to #1348, but I think the new CLI argument works.

[SachinVin]

Why is argc a reference?

[robyn-dressler]

Good question, I don't know. I'll pass by value instead

[LNDF]

It might be better to use an arg parsing library like Boost program_options

[qurious-pixel]

linux-sdl appimage works when entering path ./Shadps4-sdl.AppImage /path/to/eboot.bin -f or --fullscreen.
Used to ./Shadps4-sdl.AppImage --fullscreen /path/to/eboot.bin order convention, but this fails with case-sensitive error message Eboot.bin file not found. Whereas removing the switch, it boots into the game.

[robyn-dressler]

@LNDF I really would like to use a library for this, but I was hesitant to introduce a new dependency to common, because of this comment in the style documentation:

Don't ever introduce new external dependencies into Core

If that doesn't apply here, then I could rework this to use the Boost library. That would also probably resolve the ordering issue @qurious-pixel mentioned.

[LNDF]

Boost is already a dependency. You could try to open a PR in https://github.com/shadps4-emu/ext-boost adding boost/program_options.hpp using bcp.