Add proxy support for the soap & graphql controllers

[Afanas10101111]

Reason/Context

Sometimes it may be useful to forward Microcks' client to a real endpoint, so that we can implement some logic when we need a mock and when a real call. With such feature we don't have to change the url on the client's side if we want both (mock or real) behaviors.

Description

We need to reuse the logic of this enhancement for the Soap & GraphQL controllers.

Implementation ideas

Soap & GraphQL

[lbroudoux]

Thanks a lot for the great work!