move //components/payments/content/*.mojom files to //components/payments/mojom

To break dependency of //components/webdata_services on //components/payments/content after
landing https://codereview.chromium.org/2801513002/

BUG=711952

Review-Url: https://codereview.chromium.org/2811593009
Cr-Commit-Position: refs/heads/master@{#464877}
57 files changed