[paymentrequest] Redirect specs to the Web Payments WG versions (#69)

This pull request replaces the documents in the specs folder with pointers to the migrated documents in the W3C Web Payments WG repo. They also include pointers to the old documents in the archive of this repo.
You can view, comment on, or merge this pull request online at:

  https://github.com/WICG/paymentrequest/pull/69

-- Commit Summary --

  * Redirect specs to the Web Payments WG versions

-- File Changes --

    M specs/architecture.html (225)
    M specs/basic-card-payment.html (194)
    M specs/method-identifiers.html (77)
    M specs/paymentrequest.html (1087)

-- Patch Links --

https://github.com/WICG/paymentrequest/pull/69.patch
https://github.com/WICG/paymentrequest/pull/69.diff

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Reply to this email directly or view it on GitHub:
https://github.com/WICG/paymentrequest/pull/69