Add search functionality

[mvaaltola]

Search currently displayed vectortile layer(s) for features when user types a query into the search field. Display search suggestions in a dropdown, and zoom to selection if user clicks on a suggestion. Automatically zoom to first suggestion if user types a query and hits enter.

[mvaaltola]

User writes a search query and hits enter or the search button. Only matching features are shown on the map. Search is exited by pressing a X (close) button that appears after searching, after which all features are shown again and the search field is emptied.