org-clock: Add an option to not show the file column in clock report

* lisp/org-clock.el (org-clocktable-defaults): Add `hidefiles'.
(org-dblock-write:clocktable): Implement not showing files when
`hidefiles' is true.
* lisp/org-pcomplete.el: Add `hidefiles'.

lisp/org-clock.el

@@ -307,6 +307,7 @@ string as argument."
    :link nil
    :narrow '40!
    :indent t
+   :hidefiles nil
    :formula nil
    :timestamp nil
    :level nil
@@ -2406,6 +2407,7 @@ the currently selected interval size."
 	   (ws (plist-get params :wstart))
 	   (ms (plist-get params :mstart))
 	   (step (plist-get params :step))
+	   (hide-files (plist-get params :hidefiles))
 	   (formatter (or (plist-get params :formatter)
 			  org-clock-clocktable-formatter
 			  'org-clocktable-write-default))
@@ -2460,7 +2462,9 @@ the currently selected interval size."
 	     ;; Even though `file-with-archives' can consist of
 	     ;; multiple files, we consider this is one extended file
 	     ;; instead.
-	     (and (consp files) (not (eq scope 'file-with-archives)))))
+	     (and (not hide-files)
+		  (consp files)
+		  (not (eq scope 'file-with-archives)))))
 
 	(funcall formatter
 		 origin

lisp/org-pcomplete.el

@@ -429,8 +429,9 @@ switches."
 			   ":tstart" ":tend" ":block" ":step"
 			   ":stepskip0" ":fileskip0"
 			   ":emphasize" ":link" ":narrow" ":indent"
-			   ":tcolumns" ":level" ":compact" ":timestamp"
-			   ":formula" ":formatter" ":wstart" ":mstart"))))
+			   ":hidefiles" ":tcolumns" ":level" ":compact"
+			   ":timestamp" ":formula" ":formatter"
+			   ":wstart" ":mstart"))))
 
 
 ;;; Finish up