docs: otp guide updates (#686)

* docs: otp guide updates

Stopgap updates to OTP guide to help upcoming hackathon participants. More significant updates are coming in the next few weeks.

* docs: separate developer and sender in guide

* docs: add badges for methods

* prettier

* Update docs/src/content/docs/guides/make-onetime-payment.mdx

Co-authored-by: Max Kurapov <[email protected]>

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Co-authored-by: Max Kurapov <[email protected]>

Author: melissahenderson