Manage cards link on checkout page

[jacstn]

1. Objective

This PR adds a link to checkout / payments / credit cards page, to easily go to managing cards page where a user can delete cards.

2. Description of change

Just adds link and TH translation

3. Quality assurance

• Platform version: Magento CE 2.2.3.
• Omise plugin version: Omise-Magento 2.7.
• PHP version: 7.0.16.

✏️ Details:

1. Make sure you have saved any credit cards.
   Go to checkout, choose credit card payment, see if Manage your cards link is available. Click on the link, and see if you are moved to customer panel/managing cards page.

2. Make sure you don't have any saved cards.
   Manage your cards link should not be visible.

4. Impact of the change

N/A

5. Priority of change

Normal

6. Additional Notes

N/A

[jonrandy]

"Select a card you want to proceed" doesn't make sense - "Select a card to proceed" is better

[jonrandy]

Just a language change (English). Not related to these changes, but not spotted before

[guzzilar]

I'm not quite really sure in what case that user want to jump out from "finishing purchasing an order" to "delete card". Do you have any real use case that have been reported to us before? @jacstn

[jacstn]

for me @guzzilar it is easy to imagine when you come back to the store after some time and you see some old cards saved... no need to search in platform how to manage them, easy to imagine that it will be quite useful.

[jacstn]

but target="_blank" could be better here.

[guzzilar]

@jacstn Still don't see much point in a real use case here.
Maybe we feel like we need a link to be there because we mostly "test" the system so there will be a lot of cases where we feel the need to jump between "deleting cards" and "placing an order" (as we have to test save card several times to the point that we feel that it would be nice to have a quick access to delete all the cards we saved).

But in reality, will you just come to the checkout page just to delete a saved card?
Or will user really going to intervene themselves from finishing the purchase to delete a card first?

[jacstn]

you will not go specifically to the checkout page to delete saved card, it is just option.