refactor: dockerfile adjustments, add lefthook and megalinter

[nightah]

This change adjusts the Dockerfile with enhancements only available in newer Docker and Buildx releases.

I have also added LeftHook and MegaLinter with an appropriately adjusted configuration for linting.

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Warnings	Elapsed time
✅ ACTION	actionlint	1		0	0	0.19s
✅ BASH	bash-exec	11		0	0	0.03s
✅ BASH	shellcheck	11		0	0	0.14s
✅ BASH	shfmt	11	0	0	0	0.01s
✅ DOCKERFILE	hadolint	1		0	0	0.28s
✅ EDITORCONFIG	editorconfig-checker	39		0	0	0.23s
✅ YAML	prettier	5	0	0	0	0.51s
✅ YAML	yamllint	5		0	0	0.27s

See detailed report in MegaLinter reports
Set VALIDATE_ALL_CODEBASE: true in mega-linter.yml to validate all sources, not only the diff