Deprecate Markdown Training & Test Data

[wochinge]

Proposed changes:

• deprecate Markdown Training Data (reading and writing)
• Story reading / writing
• NLU reading writing
• Response Selector reading / writing
• skip printing deprecation warnings when converting training data

Status (please check what you already did):

• added some tests for the functionality
• updated the documentation
• updated the changelog (please check changelog for instructions)
• reformat files using black (please check Readme for instructions)

[wochinge]

replaced tmpdir as tmpdir is not a Path but of type py.path.local

[wochinge]

@edmacovaz @degiz Re Rasa X:

This change will lead to warnings in the terminal when using Rasa X with Markdown format. I added switches so that it's possible to suppress them, but the question is whether this actually needed. What do you think?
I think the more important TODO item would be to have a warning for the future deprecation in the Rasa X UI.

[degiz]

Looks great, thanks a lot for working on that! 🚀 🚀 🚀
Not putting Approve because of the docs, I'm not sure if the deprecation is communicated well enough.

I added switches so that it's possible to suppress them, but the question is whether this actually needed

I think yes. The way it's used in this PR makes sense to me, because we def. don't want these deprecation warnings when rasa data convert is being used.

future deprecation in the Rasa X UI

This will be more tricky for sure. The closest thing we have now are the warning for the inconsistencies in the domain, and that's a separate endpoint. Probably will have to do something similar with the training data.

[wochinge]

because we def. don't want these deprecation warnings when rasa data convert is being used.

Sorry, I meant if we should use the switches when reading data within Rasa X (e.g. for Integrated Version Control). The deprecation warnings would "only" show up in the server logs which means that only developer can see them. If we use the switches in Rasa X we also have to consider that users might use Rasa X with older Rasa Open Source version where the readers / writer don't have the switch.

[erohmensing]

I think the docs look okay, @degiz what would you add to clarify further?

[degiz]

@erohmensing I don't have anything specific on mind, just wanted anyone from CSE to confirm 👍

[wochinge]

@edmacovaz what do you think about the Rasa X implications?

[wochinge]

@edmacovaz Have you seen my comment above?

[edmacovaz]

@wochinge Sorry, I missed that one. I'll try to find some time to think about this once the squad organisation stuff has settled a little. I guess this still falls with you and the Enable team (where I think there's an open question about where you get your design help from). Does that work for you?

[wochinge]

Mhm, could also be the CDD squad 🤔 Works for me 👍🏻