Split database URL into fields

[BobyMCbobs]

Issue

Depending on the environment, it may important to ensure that the password and other fields of the database URL are kept very secure.
If something such as the database password is able to be set in a separate environment variable, then it can be stashed away separately and securely away from the string.

Also, when deployed in a container orchestration system such as Kubernetes and the database deployed with something like https://github.com/zalando/postgres-operator, then the database password could be fetched from a secret which is generated by the database operator instead of put again into a separate secret.