Polling stations import / export

[RaduCStefanescu]

As an admin user I want to be able to import a list of Polling stations in the application and export a csv with the example format needed for importing.

Option only allowed for the master admin account (an ngo admin belonging to an ngo that has the organizer flag set to true)

Backend needed. To be implemented when code4romania/monitorizare-vot#237 is done.

UI available here: https://www.figma.com/file/61NHR7fwmV1Dsv4Pb6F8T7/code4ro_mv_user-management_2018.04.21-(Copy)?node-id=754%3A0

Add two new button on top of the counties page (depends on #215).

Needed functionalities:

• add the button for exporting the current polling stations list, the button should be available on top of the counties list; use the endpoint GET api/v2/polling-station/csvFormat - downloads existing polling stations in csv format
• add the button for importing the polling stations list, the button should be available on top of the counties list; use the endpoint POST api/v2/polling-station/import - for importing the csv file

Polling stations data model:

• id, address, coordinates, adminTerritoryCode, IdCounty, TerritoryCode, Number

Please use bootstrap classes as much as possible and avoid adding custom css styles to keep the codebase clean & consistent. The new UI should be as similar as possible to the one in figma, not pixel perfect.

Also, make sure all texts are extracted in translation files.