GitLab

* Building the interstitials for the apps
* Show the interstitial on the EntityViewer page
* Fix tests
* Update styles for the BrowserInterstitialInstructions component
* Add nullability to a storage getter
* Add hide the in-app-search input field in production environment
* Reorder imports

Notable:
- Typescript v3 -> v4
- Storybook v5 -> v6
  - changed stories from `storiesOf` format to component story format
- Postcss-loader v3 -> v4
- D3 v5 -> v6

Add licence header to all typescript files in the src and stories directories

- Use the real api endpoint to get search-related data
- Update typings of search-related data
- Show message when no matches were found
- Add an interface element for clearing the search field
- Show a link to Genome Browser when at least one species has been selected
- Update the way that the data about selected assembly is passed in redux action
- Rename CloseButton to ClearButton (better reflects its functionality)
- Show tooltip when hovering over popular species buttons
- Show tooltip when hovering over the hint button (right-hand corner of species search field)
- Remove the remaining SpeciesSelector stories (they don't serve any real purpose anymore)
- Fix tests
- Remove unused mock data for species selector

Also add shared components that are building blocks for AutosuggestSearchField:
- Input
- SearchField