add arm64 Docker image support

[Mnikley]

Purpose

This PR adds multi-architecture (amd64 and arm64) support to the following Docker images:

• lasuite/meet-backend
• lasuite/meet-frontend
• lasuite/meet-frontend-dinum
• lasuite/meet-summary
• lasuite/meet-agents

Changes

• Added QEMU setup for cross-platform emulation
• Added Docker Buildx configuration for multi-platform builds
• Configured all build jobs to produce both linux/amd64 and linux/arm64 images
• Enabled GitHub Actions cache to optimize build performance

[sonarqubecloud]

Quality Gate failed

Failed conditions
10 Security Hotspots

See analysis details on SonarQube Cloud

[Mnikley]

requires to add the following actions to the allow list:
- docker/setup-qemu-action@v3
- docker/setup-buildx-action@v3

[lebaudantoine]

Hi @Mnikley,

Sorry for the overlap, I just merged PR #981, which addresses the same changes. I’ll go ahead and close your PR for now.

If there’s anything additional in your branch or you’d like to build on top of the merged changes, please feel free to rebase on main and reopen it.