Refactor CI to push from main

[julien-marchand]

Description

Refactor CI to push from main

Motivation

Have more transparency on where images have been built. Ensure all deployed software has been built from main. Streamline the release process. Ensure no docker image is pushed from branches and forks.

Tasks

• [ ] Reuse locally built images when running e2e tests
• [ ] Don't push docker images on branches/PR
• [ ] Push images at the end of the workflow on main

Risks

• [ ] Make it harder to debug failures in e2e related to runners/CI