Use 'sinon' for fake timers in tests

[fullkomnun]

What does this implement/fix? Explain your changes.

• periodic-payment-test is currently the e2e tests that has the longest runtime (~ 1h)
• Most time is spent waiting for 'node-cron', however instead this test can use 'sinon' for faking timers for granular control over timers for testing all kinds of use-cases and avoiding tests relaying on waiting which can lead to flacky test and/or excessive waiting

Does this close any currently open issues?

Nope

What commands can I run to test the change?

Run 'periodic-payment-test' locally and/or in ci:

1. NF_SERVICES_TO_START=blockchain,client,deployer,mongodb,optimist,rabbitmq,worker ./bin/setup-nightfall
2. NF_SERVICES_TO_START=blockchain,client,deployer,mongodb,optimist,rabbitmq,worker CONFIRMATIONS=1 WHITELISTING=disable ./bin/start-nightfall -g -d
   [in another terminal]
3. docker wait nightfall_3_deployer_1 (wait for deployer to finish)
4. CONFIRMATIONS=1 npm run test-periodic-payment

Any other comments?

• These changes decrease total runtime of 'periodic-payment-test' from '1h 0m 40s' to '30m 50s' - a 50% decrease in runtime!
• Can perhaps use @sinonjs/fake-timers directly instead