Multi-platform docker image support

[matheusfm]

These changes add support for building multi-platform docker images, through the make buildx command, and bump alpine base image version.

This is how Kubebuilder generates the Makefile for generated-projects.

Closes: #253

I've built the image ghcr.io/undistro/popeye:v0.11.3 with these changes. See the supported architectures:

trivy image ghcr.io/undistro/popeye:v0.11.3 

2024-02-09T11:16:34.624-0300    INFO    Vulnerability scanning is enabled
2024-02-09T11:16:34.624-0300    INFO    Secret scanning is enabled
2024-02-09T11:16:34.624-0300    INFO    If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2024-02-09T11:16:34.624-0300    INFO    Please see also https://aquasecurity.github.io/trivy/v0.48/docs/scanner/secret/#recommendation for faster secret detection
2024-02-09T11:16:36.410-0300    INFO    Detected OS: alpine
2024-02-09T11:16:36.410-0300    WARN    This OS version is not on the EOL list: alpine 3.19
2024-02-09T11:16:36.410-0300    INFO    Detecting Alpine vulnerabilities...
2024-02-09T11:16:36.413-0300    INFO    Number of language-specific files: 1
2024-02-09T11:16:36.414-0300    INFO    Detecting gobinary vulnerabilities...

ghcr.io/undistro/popeye:v0.11.3 (alpine 3.19.1)

Total: 0 (UNKNOWN: 0, LOW: 0, MEDIUM: 0, HIGH: 0, CRITICAL: 0)

[matheusfm]

Hi @derailed
Any feedback or suggestions on this?
Please let me know if there's anything I can do to help move this forward.

[eugenestarchenko]

It would be great to have this!