[BUGFIX] Show folder icons in ElementBrowser file tree

The folder icons are now also shown in the ElementBrowser file tree,
but without context-menu. As the icon link handling provided by the
general FolderTree wrapIcon function does not match in ElementBrowser
mode, an own implementation of this function is introduced in
ElementBrowserFolderTreeView.

Resolves: #69802
Releases: master, 7.6
Change-Id: I4854a69ac5b5459d3e284472ccad5c602a277883
Reviewed-on: https://review.typo3.org/46212


Reviewed-by: Michael Oehlhof <typo3@oehlhof.de>
Tested-by: Michael Oehlhof <typo3@oehlhof.de>
Reviewed-by: Frans Saris <franssaris@gmail.com>
Tested-by: Frans Saris <franssaris@gmail.com>