Remove ServerBuilder::configure

[fakeshadow]

PR Type

Refactor

PR Checklist

Check your PR fulfills the following:

• Tests for the changes have been added / updated.
• A changelog entry has been made for the appropriate packages.
• Format code with the latest stable rustfmt

Overview

Remove ServerBuilder::configure API and config module.

Reason:

1. There is one potential footgun with config module. It's that it pack multiple service factory calls into one future. This result in any failure of service would trigger restart of all the packed services. This could be an issue when service factories have dependent on external state.

2. actix-server right now have a strict 1:1 mapping between socket and service. This lead to duplicated service types across worker threads and preventing service state share when multiple sockets can/should share one service. config module get in the way of resolving this issue as it has a unique set of API.

3. Nothing use config module.

The removal would be tempoaray until socket/service mapping is figured out.