feat(hook): Add instance of MailAlert to hook

[Kaikina]

Questions	Answers
Description?	It makes sense to add the instance of the MailAlert into the hook params as we probably want to use its properties inside our hook code. For instance, it would be great to have a practical access to id_product_attribute.
Type?	improvement
BC breaks?	no
Deprecations?	no
Fixed ticket?	NA
How to test?	Register this hook, access the passed array and test that mailAlert key is set and is an instance of the MailAlert object that is executing the hook.

[ps-jarvis]

Hello @Kaikina!

This is your first pull request on ps_emailalerts repository of the PrestaShop project.

Thank you, and welcome to this Open Source community!

[boherm]

Thanks for your contribution! I agree with you, that could be nice to have :)

[Kaikina]

I updated to "id_product_attribute". I didn't see it was a static function (I don't like static functions). So no way of passing "$this". But actually, I think the only missing information while using the hook was the id_product_attribute, so I added it.

[Kaikina]

May we merge this branch ?