[Task] No image tag replacement flag for the generate command

[taorepoara]

What should be done

The default behavior of Dofigen is to replace Docker image tags by there corresponding digests in order to have the control on the real docker image used.

It could be nice to add a --no-replace-tags flag to let the possibility to disable this behavior for the users that don't want it.

Technical recommandation

Do not replace never the tags in the effective of the lockfile in order.
The tags are replaced at the end of the generate and effective commands if the flag is not present.