[FEATURE] Use process.env.NEXT_CACHE_HANDLER_PATH

[vicb]

As noted by @conico974 in #143 (comment), Next now allows setting the cache handler via process.env.NEXT_CACHE_HANDLER_PATH

Consider using that for Open Next.

[conico974]

The way i see it we should do it in the aws repo.
We use the esbuild replacement plugin to apply this env variable on Next 15. This will also allow you to use this same replacement plugin to remove the require.resolve

In the future it would make sense to allow to customize this in the open-next.config.ts file directly, maybe add a build option that would allow to customize the esbuild build process itself.
We could even undeprecate (or reimplement) the experimentalBundledNextServer options and this would allow you to more easily fix stuff in NextServer directly