Ensure tags are defined asking interactively for them

[lucmos]

No description provided.

[Flegyas]

I'm not sure about the multi-run setting. What happens if we launch n different runs with no tag set? Are we prompted for all of the tags at once or in between runs?

[lucmos]

Is there a way to get the information on whether or not we are in multi-run from python? Maybe somewhere from HydraConfig()?

If yes, we could:

• Raise an error if we are in multi-run and no tags are provided, instead of asking interactively
• Ask for tags only in job 0, but I think it will be hard to propagate the tags to the other jobs

Moreover, it would be nice to log a common tag between all runs in a multi-run, e.g. multirun-timestamp or multirun-{hash of the options}. This will be probably easier to implement with an interpolation in the configuration