[nostalgia] Split part of Core out into Foundation, add module system

src/nostalgia/player/app.cpp

@@ -3,6 +3,7 @@
  */
 
 #include <nostalgia/core/core.hpp>
+#include <nostalgia/foundation/media.hpp>
 
 using namespace nostalgia;
 
@@ -33,6 +34,7 @@ static int updateHandler(core::Context *ctx) noexcept {
 	}
 	spriteX += xmod;
 	spriteY += ymod;
+	//constexpr ox::StringView sprites = "nostalgia";
 	for (unsigned i = 0; i < sprites.len(); ++i) {
 		const auto c = static_cast<unsigned>(sprites[i] - ('a' - 1));
 		core::setSprite(ctx, i, spriteX + 8 * (static_cast<int>(i) + 1), spriteY, c, 0, 0, 0);