[REQ] Move phpLegacySupport option from PhpSymfonyServerCodegen.java to AbstractPhpCodegen.java

[arderyp]

Is your feature request related to a problem? Please describe.

the phpLegacySupport flag is available to the php-symfony generator, and it produces more strongly typed code. It is not available, however, in the main php generator.

Describe the solution you'd like

I think this option should be moved up to the parent AbstractPhpCodegen class so that all child php generators can use this option. Here is the logic in question.

Describe alternatives you've considered

Additional context