Rewrite:

- moved constants GRAVITY_* from boot.php to Friendica\Model\Item
- also rewrote some array initialization:

From:
````
<?php
$arr = [];
$arr['foo'] = "FOO";
````

To:
````
<?php
$arr['foo'] = "FOO";
````
- added a few type-hints

src/Module/Item/Ignore.php

@@ -25,6 +25,7 @@ use Friendica\BaseModule;
 use Friendica\Core\Session;
 use Friendica\Core\System;
 use Friendica\DI;
+use Friendica\Model\Item;
 use Friendica\Model\Post;
 use Friendica\Network\HTTPException;
 
@@ -49,7 +50,7 @@ class Ignore extends BaseModule
 
 		$dba = DI::dba();
 
-		$thread = Post::selectFirst(['uri-id', 'uid'], ['id' => $itemId, 'gravity' => GRAVITY_PARENT]);
+		$thread = Post::selectFirst(['uri-id', 'uid'], ['id' => $itemId, 'gravity' => Item::GRAVITY_PARENT]);
 		if (!$dba->isResult($thread)) {
 			throw new HTTPException\NotFoundException();
 		}