BaseGrid: Remove timeline specifics

Timeline is a separate implementation. Base grid is what it's
name implies, a base implementation.

Author: nilmerg

library/Notifications/Widget/TimeGrid/BaseGrid.php

@@ -7,7 +7,6 @@
 use DateInterval;
 use DateTime;
 use Generator;
-use Icinga\Module\Notifications\Widget\Timeline\FutureEntry;
 use ipl\Html\Attributes;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\HtmlElement;
@@ -422,20 +421,6 @@ final protected function yieldFixedEntries(Traversable $entries): Generator
             }
 
             $rowStart = $position + $rowStartModifier;
-
-            if ($entry instanceof FutureEntry) {
-                $gridArea = $this->getGridArea(
-                    $rowStart,
-                    $rowStart + 1,
-                    1,
-                    $gridBorderAt + 1
-                );
-
-                yield $gridArea => $entry;
-
-                continue;
-            }
-
             if ($rowStart > $lastRow) {
                 $lastRow = $rowStart;
             }

library/Notifications/Widget/Timeline.php

@@ -187,7 +187,10 @@ public function getEntries(): Traversable
             }
 
             if (! $entryFound && ! $this->minimalLayout) {
-                yield (new FutureEntry())->setPosition($maxPriority - $rotation->getPriority());
+                yield (new FutureEntry())
+                    ->setStart($this->getGrid()->getGridStart())
+                    ->setEnd($this->getGrid()->getGridEnd())
+                    ->setPosition($maxPriority - $rotation->getPriority());
             }
         }