Improve PHPStan to level 5

[mvorisek]

ignores were generated by:

$d = json_decode(<<<'EOT'
<<< output from vendor/bin/phpstan analyse --error-format=json
EOT, true)['files'];

foreach ($d as $f => $vs) {
    $messagesUnique = [];
    foreach ($vs['messages'] as ['message' => $m]) {
        $messagesUnique[$m] = true;
    }
    $messagesUnique = array_keys($messagesUnique);
    
    foreach ($messagesUnique as $m) {
        echo '        -' . "\n"
            . '            path: \'' . preg_replace('~^/__w/ui/ui/~', '', $f) . '\'' . "\n"
            . '            message: \'~^' . preg_replace('~\'~', '\'\'', preg_replace('~\\\\:~', ':', preg_quote($m, '~'))) . '$~\'' . "\n";
    }
}