Refactored search interface code

Refactored search interface code:

• New folder layout, improved filenames. Created new subfolders: input, menus and results. Renamed files so that the functionality can better be guessed by simply looking at the file name.
• Created custom components for FilterMenu and items in it (see search/menus/FilterMenu.js). This greatly simplified the layout of search/menus/FilterMainMenu.js making the addition of new menu items a breeze. These new components are structured very similarly to how MaterialUI deals with Tabs.
• Added new "Access" menu and InputRadio component. Here one can control the visibility of the calculations (controls the owner parameter in API calls.)
• Refactored the Actions -component.
• Several small performance tweaks.

With this refactoring done, I will continue integrating the new search interface to Uploads/Datasets and removing the old search code.

@mscheidg: can you check that the new folder layout and filenames make sense?