friendica-5847 Console Cache List command doesn't work

- Added $prefix to all CacheDriver
- Moved hostname magic to CacheDriver
- Added test for getAllKeys()

tests/src/Core/Cache/ArrayCacheDriverTest.php

@@ -7,11 +7,6 @@ use Friendica\Core\Cache\ArrayCache;
 
 class ArrayCacheDriverTest extends MemoryCacheTest
 {
-	/**
-	 * @var \Friendica\Core\Cache\IMemoryCacheDriver
-	 */
-	private $cache;
-
 	protected function getInstance()
 	{
 		$this->cache = new ArrayCache();