This patch adds the file name to the metadata panel, after the license
item. The namespace prefix is included and set to a static 'File:'.
The Title class already converts underscore to spaces.
The icon is from @Pginer-WMF.
PS: This has been a frequent annoyance for me, I'm glad to be working
on this patch!
Bug: T76680
Change-Id: I7d1f4ce67a6776ac017f8afe49cb3102b267af5c
