web: Add better alerts for insight data processing

Created by: unclejustin

There are two more states to address when populating data for a backend insight.

1. Insight has no data
2. Insight data is still incomplete

Here are the proposed overlays to address them. The easiest way to see them in real time is via storybook.

yarn storybook:web

Here are the original designs in Figma

Note: I have deviated from the designs slightly. I couldn't get the gradient to work properly. If @AlicjaSuska feels strongly about it, I will pair up and get it done 💪 but in the meantime here is my compromise.

Also, the designs have the overlay not covering the X-axis keys like so:

For simplicity's sake, I am covering them. Without going into detail It is much simpler to do it this way. Again, if Alicja feels strongly about it, I can make it happen but it will increase the complexity quite a bit.

Insight has no data

Insight still fetching data

https://user-images.githubusercontent.com/1855233/129814887-004c8d36-5b4c-4d90-b194-7e63b8fb9d58.mov

Related to #18708 (closed)