Add a way to disable native codegen

[CompeyDev]

Lune exposes no way to disable Luau's JIT, which is enabled by default for all cases, except for hardware where which Luau does not support codegen for. In general, it makes sense to provide the most optimized configuration possible as a runtime by default.

lune/crates/lune-std-luau/src/lib.rs

Lines 79 to 81 in ff83c40

	lua.enable_jit(options.codegen_enabled && !env_changed);
	let function = chunk.into_function()?;
	lua.enable_jit(true);

Although rare, it is sometimes possible for JIT to be slower in some cases, or the user might want more fine-grained control over what aspects JIT is applied to (preferably using the @native attribute). For such use-cases, it makes sense to expose an environment variable and/or flag which can toggle JIT in the runtime.

Other runtimes like Bun for JavaScript already expose such options in a similar way.