Expose WebStack for external wrapper support in downstream crates (#542)

* add public ServiceConfig::register constructor to support external configuration (#250)

* fix: doctest ServiceConfig::register() error (#250)

* add unit testing for ServiceConfig::register()

* replace pub(crate) to pub in ServiceConfig::new() (#250)

* replace pub to pub(crate) for ServiceConfig::new() and add pub for mod ntex::web::stack instead

* remove unsed DefaultError import in config.rs tests

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Co-authored-by: RuangyotN <ruangyotn@skyller.co>

ntex/src/web/mod.rs

@@ -82,7 +82,7 @@ mod route;
 mod scope;
 mod server;
 mod service;
-mod stack;
+pub mod stack;
 pub mod test;
 pub mod types;
 mod util;