Add Importers Mockups

[carlosthe19916]

This PR adds a proposal of how the new Importers Page might look like after the UI Revamp.

Rename Importers by Data Sources => I think Importers is an internal terminology that was leaked in the UI. The whole system data will be populated by the Importers and hence I thought it would make sense to rename it as something like Data Sources. Feedback is welcome.

• No Pagination and all importers are rendered in the page.
  • We will never deal with thousands of importers and I think it would be better to render all rows without limiting the user to see only the first 10 ones. Feedback is welcome :)
• We do not use a Table anymore but a DataList
  • To render more data condensed in a single row I think it would make sense to replace our old Table. Tables force us to render only one type of data per column
• Each row has an icon at the Left. That icon should indicate the latest outcome of any know execution of the Importers.
• Replace the Expandable area by a Left Drawer.

[carlosthe19916]

I did not add logic to the components as these are just mockups and there is no need to too much code. As long as the Stories render an understandably the spirit of the page, it should be enough.

[kahboom]

I love it! Just FYI, after merge I'll be moving these under a section called "v2.1" to separate them from 2.0 stories in another PR shortly.