chore: Sync with JHipster 7.1.0

[juliensadaoui]

Related to #502

I removed the administrative server in the Registry, for more information see #502

fix #495 , #472

• Please make sure the below checklist is followed for Pull Requests.

• [x] All continuous integration tests are green

• [x] Tests are added where necessary

• [ ] Documentation is added/updated where necessary

• [ ] Coding Rules & Commit Guidelines as per our CONTRIBUTING.md document are followed

• [x] Update JHipster Dependencies version to 7.1.0

• [x] Update Spring Boot version to 2.4.7

• [x] Update Node version to 14.17.1

• [x] Upgrade from Angular 10 to Angular 12

• [x] Remove the administrative server

• [x] Add new unit tests for registry module (client side)

• [x] Build Docker is OK

• [x] Check if the JWT authentication works

• [x] Check if the OAuth2 authentication works

• [x] Check if the registry works with microservices and gateways

[juliensadaoui]

I have tested the registry with microservices connected to it and it works fine.