Function load_next_js_template 

pub async fn load_next_js_template(
    template_path: &str,
    project_path: FileSystemPath,
    replacements: &[(&str, &str)],
    injections: &[(&str, &str)],
    imports: &[(&str, Option<&str>)],
) -> Result<Vc<Box<dyn Source>>>

Loads a next.js template, replaces replacements and injections and makes sure there are none left over.