Sync with JHipster 7.6.0

[juliensadaoui]

Overview of the issue

I open this ticket to sync the registry with jhipster 7.6.0. Below, please find a list of major changes.

• Update JHipster Dependencies version to 7.6.0

• Update Spring Boot version to 2.6.3

• Update Node version to 16.13.1

• Update Angular version to 12

• Fix breaking changes & unit tests (client side)

• [X] Checking this box is mandatory (this is just to show you read everything)

[pascalgrimaud]

Adding a bounty as it's a lot of work