Rework palette information into palettes.dat

[AaronVanGeffen]

Building on the font information having already been moved to fonts.dat (#24342), this PR reworks the palette information, such that the game can be launched without G1. This would be useful for 'onboarding' purposes, e.g. selecting the game path if it cannot be automatically detected. Currently, this has been implemented using various platform-specific dialog toolkits (e.g. Zenity/KDialog).

Previously, there were several places where palettes were defined, and in different orders, no less. This has now been harmonised, compiling all palette info into its own graphics file, palettes.dat. This collects our extended (remap) palettes together with the vanilla (remap) palettes.

As part of dumping all palettes, the old text palette was also dumped. However, as of #25658, this is no longer necessary. It should probably be removed from this PR as well.

[Gymnasiast]

As part of dumping all palettes, the old text palette was also dumped. However, as of #25658, this is no longer necessary. It should probably be removed from this PR as well.

Has this been done already?

[AaronVanGeffen]

As part of dumping all palettes, the old text palette was also dumped. However, as of #25658, this is no longer necessary. It should probably be removed from this PR as well.

Has this been done already?

Thanks, it has been done now.

The commit introducing the OnboardingScene has also been split off to a separate branch, removing it from this PR. With that, I think this is ready for review.

[mixiate]

I tested this and didn't find any differences.

Tested with diffing giant screenshots from the command line of various parks (nedesigns, dkmp, etc).

Made a very quick test with glass scenery:
transparenttest.zip

Tested a few ui screenshots and things that use the marker palettes.

Palettes.dat doesn't get built with msvc, gym has a patch for it though as I can't leave it as a suggestion here.

Have only briefly looked at the code but seems okay.

[AaronVanGeffen]

The rework of palette sprites has been split off to #25844. That just leaves the update to gxc in OpenRCT2/libsawyer#9 to finally wrap this up.

[Gymnasiast]

Seems to work. I tried compressing the PNGs with zopflipng but that just caused some very weird effects.

@mixiate Could you give it one more test?

[mixiate]

Did the same tests as before and it's all good.