Remove why_we_collect_es from all configs

[dcolondavila]

In the join page when making the change from English to Spanish the property (key) called "why_we_collect" in the Spanish version appears as "why_we_collect_es", generating a problem because when making the dynamic change of the text of the web page does not find this key ("why_we_collect") in the JSON file when the fetch is done. Therefore, we have decided to create this property in the key "ES" in each of the JSON files of the studies.

Note: Remove why_we_collect_es from all configs.

[shankari]

We also need to make the same changes to the stage_ configs. those are used by Google and Apple during App Store Review, and I would like to keep them updated.