XWIKI-11154: Impossible to download extension file from REST when the extension file link is a URL that does not provide any content type

(cherry picked from commit 26178ba074bc01688799e33ca2384b0d32725a30)
XWIKI-11143: Add support for URL source in office viewer macro

(cherry picked from commit c150fb86cb163ba2f11de0ceba893ea7a87e3d09)