[token-server] Extend rate limiting to token rewards

Summary: Looks like we are getting some scripted token reward claims. They may be manual, as they do seem to be going to different wallets with different use cases (not consolidating at one wallet). But they are coming in at the same time from the same IP address.

Test Plan: npm test

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D16714