Payment Request's implementation report

Hi,
I've generated the first "official" implementation report for Payment
Request covering Safari, Chrome, Firefox, and Edge.

IMPORTANT: the report excludes manual tests, which I will add soon.

https://w3c.github.io/test-results/payment-request/all.html

If there are other implementing user agents that should be included,
let me know and I can provide instructions on how to generate the
result.

We will try to keep publishing periodically as stuff gets implemented.
To go to Recommendation, two of those columns need to be all green.

Again, help doing manual testing is always appreciated.

Kind regards,
Marcos