Use root-hooks or global-fixtures to set up Mocha test and clean the db

[tomivm]

Create a root Mocha file for set up test. Mock nodemailer and Clean dB.
Evaluate the possibility of including it with --require or a config file.
https://mochajs.org/#root-hook-plugins
https://mochajs.org/#global-fixtures
https://mochajs.org/#configuring-mocha-nodejs