Read DB config from Yaml file. Update maine page style

TODOs:

- [x] ~~Read from database.yml file~~ this doesn't work, because loading the yaml file inside the `database.rb` file will not replace the environment variables values inside the Yaml config, hence we will have an invalid database config.
- [x]  Update maine page style
- [x] Run `test-end-to-end.sh` to assert all works as expected