[Lens] Move dimension settings to flyout

[flash1293]

To give more space for complex configuration, the dimension settings should move from a popover to a flyout:

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[timroes]

I just want to raise awareness that we make the decicion to have the field selector first and "operation" second a very conscious decicion that time, to put "data first" for the user in contrast to the existing visualize editor experience. This suggestion is turning this around again, and have the user first go with an operation and than a field for it, and thus being significanly more similar to the existing visualize editor experience (while we still group similiar aggregations into one operation), but have first operation, then field, then parameters.

I am not saying that I am against that change or the new design, I just want to bring that again to awareness and want to make sure we're making this UX flow change with the same awareness we did the initial change. Ideally I'd prefer if we could take the both ways in a comparison into usability testing. cc @cchaos

[cchaos]

You are absolutely right and we are still optimizing for that data-first pathway which we do through the fields panel and drag and drop. This is the first interaction we want users have with Lens. Find your field in the list, look at the type of data it contains, now add it to the preview panel, Lens will do the rest.

Users will mostly enter the configuration panel mainly if they want to change the function or details of the function. Which is why the list of functions is displayed in full instead of hidden behind a select input. It also then displays the "order of operations" and in how we create the display name, ie. "Sum of bytes".

So again, we are still optimizing for the data-first approach, just not within the configuration panel, but via the fields panel.