WIP: Feat/Stripe: Added more object of the stripe products categorie

[nielsbrakel]

NOTE: WIP Just looking for some feedback :)

What kind of change does this PR introduce?

1. Added new product objects: coupons, promotion_codes, tax_codes, tax_rates and shipping rates

What is the current behavior?

Added more object to make the wrapper more complete

What is the new behavior?

You can now access more information from stripe

Additional context

This is still a WIP so will place some comments on my own code to check some things.