Refactoring (List): filter section

[Konstiman]

This PR introduces the 2nd part of the List component refactoring: the refactored search/filter/sort subcomponent.

The new code can be tested by building the application with MODERN_FRONTEND=true.

Main features:

Redux:

• Three new actions: SEARCH, FILTER and SORT. They are handled in the list reducer.

Components:

• The components/ directory now contains only container components and the templates/ directory contains only presentational components, as it's described here.
• New components for the search box, filter dropdown, sort dropdown and sort buttons have been created: each of the components consists of two files: a presentional component (template) and a logical component (that connects it to the store).
• From these components, three templates for different data integrations are created: the standard filter sort, basic filter sort (no filter dropdown) and button filter sort (no filter dropdown and sort buttons instead of a dropdown).

Known bugs:

• One test fails - the problem is in triggering an onChange event in the searchbox input. fixed
• Dropdowns are bold when active (e.g. after user clicks them). This is caused by the different behavior of the react-bootstrap components. Also the structure is a bit different, so the space between the dropdowns is different. Both of these issues are probably solvable by additional CSS styling.
• Not a bug: the first letter of the dropdown options is now capitalized in the refactored version.