Move (last) get_cats_and_terms to Content\Item::determineCategoriesTerms()

- Added incomplete test

tests/src/Content/ItemTest.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Friendica\Test\src\Content;
+
+use Friendica\Test\MockedTest;
+
+class ItemTest extends MockedTest
+{
+	public function testDetermineCategoriesTerms()
+	{
+		$this->markTestIncomplete('Test data needed.');
+	}
+}