isArrayOf should be divided into different isArrayOf methods

[peter279k]

Firstly, we can consider the following code snippet in IOTA\Util\ValidatorUtil class:

    public static function isArrayOf(array $items, string $type): bool
    {
        foreach ($items as $item) {
            if (false === ($item instanceof $type)) {
                return false;
            }
        }

        return true;
    }

According to the old iota.lib.js, the related isArrayOf method has four methods. The methods are as follows:

• isArrayOfAttachedTrytes
• isArrayOfHashes
• isArrayOfTrytes
• isArrayOfTxObjects

I think it should be divided into different methods because the isArrayOf is not good enough to handle different arrays. It's not proper to use the instanceof approach to validate other non-class types.

Another approach is: enhancing the isArrayOf and let this method can support validating the different methods.

[Techworker]

You can keep the one we have now and add the others if applicable.