Use ES 5.0 keyword or text field type depending on the context

[dav3860]

It would be nice if Kibana was able to select the best string field type depending on what the user wants to do. For searches, it seems better to use text types, but for agregations it would be better to use the keyword type by default.
For example, by moving the keywords to the top of the list when choosing a field in a visualization. Or by hiding text fields by default in the list.
Another example, if we try to create a visualization by clicking a field from the Discover tab, the "text" version is selected by default. This is confusing.

[Bargs]

We have an ongoing discussion about this #7419

Would you mind adding your thoughts to that ticket? I definitely think you have the right idea, and I suspect we'll move in that direction.