Remove unused modules from api

[martinheppner]

the command "npx depcheck" shows the following list of unused node_modules. I already tested removing all of them at once - which is not working. So maybe we can try to remove one by one?

• [ ] axios
• [ ] bcrypt
• [ ] cookie-parser
• [ ] crypto
• [ ] csurf
• [ ] es6-promise-pool
• [ ] fs
• [ ] jsonwebtoken
• [ ] lodash
• [ ] morgan
• [ ] mysql
• [ ] mysql2
• [ ] node-schedule
• [ ] path
• [ ] pg
• [ ] puppeteer-core
• [ ] request
• [ ] request-promise
• [ ] @babel/core
• [ ] @babel/plugin-transform-runtime
• [ ] @babel/preset-env
• [ ] bluebird