Convert all classes to strict variable types

All variable declarations in all classes have a strict type set

Exception: constants (will be setable from PHP 8.3 on), resources (no type)

Debug\LoggingLegacy is kept as is, will be deprecated

www/lib/CoreLibs/Convert/MimeAppName.php

@@ -12,7 +12,7 @@ namespace CoreLibs\Convert;
 class MimeAppName
 {
 	/** @var array<string,string> */
-	private static $mime_apps = [];
+	private static array $mime_apps = [];
 
 	/**
 	 * constructor: init mime list