Refactor permissions check code

Directly check permissions and no subscription (uisettings is always initialized on frontend startup)
update permission directive to accept single string
add explicit management permission name

src-ui/src/app/components/document-detail/document-detail.component.ts

@@ -553,11 +553,9 @@ export class DocumentDetailComponent
   }
 
   get commentsEnabled(): boolean {
-    // TODO - Is this the only way to allow/disallow from permissions?
-    var canViewComments = false
-    this.settings.permissions().subscribe((perm) => {
-      canViewComments = perm.includes('documents.view_comment')
-    })
-    return this.settings.get(SETTINGS_KEYS.COMMENTS_ENABLED) && canViewComments
+    return (
+      this.settings.get(SETTINGS_KEYS.COMMENTS_ENABLED) &&
+      this.settings.currentUserCan('documents.view_comment')
+    )
   }
 }