Add eMerchantPay Direct Gateway

[dimitrovv]

• Adding support for eMerchantPay Direct Gateway

[dimitrovv]

@davidsantoso this PR is ready for review.

Thanks.

[dimitrovv]

@jasonwebster @davidsantoso could you please have a look at this PR.
I have restructured it to meet your Contributing Guidelines as @davidsantoso advised me here.

I will highly appreciate if someone review it and the time you invest in it. We have one more similar gateway integration to this one, but I need a feedback from you guys.

[davidsantoso]

@dimitrovv I'll try and find some time today to review. Been a busy past week.

[dimitrovv]

@davidsantoso Thanks, will appreciate it

[dimitrovv]

@davidsantoso I can see you are quite busy these days reviewing many PRs, but would you also find some time to review this briefly. We have done our best to develop this integration in the most proper way, hope you will like it.

Our merchants ping us very often, because they have an extreme need of using it.
It would be grateful if you manage to review this integration these days. We need to submit one more similar gateway to this one, but need an expert to review them.

Thanks in advance!