Remove Ecommerce Events (close #329)

[Jack-Keene]

No description provided.

[matus-tomlein]

I am a bit unsure whether we can already remove the old ecommerce events. It might be better for two things to happen (or at least one of them):

1. We update the currency conversion enrichment to work with the new Snowplow ecommerce events.
2. We implement APIs for the new Snowplow ecommerce events in the Python tracker.

Otherwise we are removing functionality without providing an alternative which makes me a bit nervous. So I would suggest keeping this PR open for maybe v2 of the tracker? But happy to discuss if there are other opinions.

[Jack-Keene]

I wasn't initially aware the ecom events were linked to the currency enrichment, so this makes sense.

In the JS tracker I think we added an enhanced ecom API, could we do something similar for Python, and add a line in the ecom event deprecation notices to use the enhanced events?

[matus-tomlein]

The enhanced ecommerce is already outdated, but we have the recent Snowplow Ecommerce that is a new plugin in the JS tracker (also in an accelerator) which we could also add here. We are currently adding it to the mobile trackers. Would be nice to have it everywhere but I think it's a larger task that needs some planning.