Changed Sandstorm menus to be more similar like other Wekan versions, make Export visible, etc.

Thanks to PizzaProgram and xet7 !

Related #3423

client/components/sidebar/sidebar.jade

@@ -288,17 +288,6 @@ template(name="boardMenuPopup")
         a.js-change-board-color
           i.fa.fa-paint-brush
           | {{_ 'board-change-color'}}
-
-    //-
-      XXX Language should be handled by sandstorm, but for now display a
-      language selection link in the board menu. This link is normally present
-      in the header bar that is not displayed on sandstorm.
-    if isSandstorm
-      li
-        a.js-change-language
-          i.fa.fa-flag
-          | {{_ 'language'}}
-  unless isSandstorm
   hr
   ul.pop-over-list
     if withApi
@@ -329,42 +318,6 @@ template(name="boardMenuPopup")
             i.fa.fa-archive
             | {{_ 'archive-board'}}
 
-  if isSandstorm
-    hr
-    ul.pop-over-list
-      if currentUser.isMember
-        li
-          a.js-export-board
-            i.fa.fa-share-alt
-            | {{_ 'export-board'}}
-        li
-          a.js-import-board
-            i.fa.fa-share-alt
-            i.fa.fa-sign-in
-            | {{_ 'import-board-c'}}
-      if currentUser.isBoardAdmin
-        li
-          a.js-archive-board
-            i.fa.fa-arrow-right
-            i.fa.fa-archive
-            | {{_ 'archive-board'}}
-      li
-        a.js-outgoing-webhooks
-          i.fa.fa-globe
-          | {{_ 'outgoing-webhooks'}}
-    hr
-    ul.pop-over-list
-      li
-        a.js-card-settings
-          i.fa.fa-id-card-o
-          | {{_ 'card-settings'}}
-    hr
-    ul.pop-over-list
-      li
-        a.js-subtask-settings
-          i.fa.fa-sitemap
-          | {{_ 'subtask-settings'}}
-
 template(name="exportBoard")
   ul.pop-over-list
     li