..F....... [ZBX-21883] changed map widgets select map field to multiselect
* commit '477ecbf78115e6984fb00781a4393fa08d471dc4':
..F....... [ZBX-21883] fixed code style
..F....... [ZBX-21883] fixed map name field, if empty, not being populated when selecting map using multiselect
..F....... [ZBX-21883] fixed PHP runtime error when remove linked "Map navigation tree" widget
..F....... [ZBX-21883] fixed coding style
.D........ [ZBX-21883] updated list of authors
..F....... [ZBX-21883] fixed JS error when trying to add Map tree element without map
..F....... [ZBX-21883] backported from feature/ZBX-21883-6.3
