Add support for <any />

[veewee]

Add support for <any />.

Fixes #559
Fixes #533

Depends on:

• Read <any /> element information php-soap/wsdl-reader#39
• Add support for <any /> php-soap/engine#21
• Add support for <any /> php-soap/encoding#29

This PR makes it possible to generate a property for the <any /> element. It is compatible with how PHP's internal ext-soap encoding works.

Generated code:

This PR makes the system understand <any /> elements.
https://www.w3schools.com/xml/schema_complex_any.asp

Based on minOccurs and maxOccurs the code generator will know to create a string, nullable<string> or list<string>.

Examples of generated code:

/**
 * @var string
 */
private string $any;

/**
 * @var array<int<0,2>, string>
 */
private array $any;

It is possible to overwrite this default type by using https://github.com/phpro/soap-client/blob/v4.x/docs/drivers/metadata.md#type-replacements

Encoding

You can read more about how encoding/decoding works and how you can overwrite the default behaviour here:
php-soap/encoding#29

Converts (bidirectionally) into:

^ {#1769
  +"customerName": "John Doe"
  +"customerEmail": "[email protected]"
  +"any": array:2 [
    0 => "<hello>world</hello>"
    1 => "<hello>worljohn</hello>"
  ]
}

For XML:

<x:GetCustomerDetailsResponse xmlns:x="http://example.com/customerdetails">
    <customerName>John Doe</customerName>
    <customerEmail>[email protected]</customerEmail>
    <hello>world</hello>
    <hello>worljohn</hello>
</x:GetCustomerDetailsResponse>