Use Enviroment Variables instead of parameters.yml

[ElectricMaxxx]

As described in http://fabien.potencier.org/symfony4-best-practices.html we should introduce enviroment variabled over parameters.

[dbu]

if i read that correctly, we essentially should create a .env file to define those env variables. for local use, that seems to be the default method to do things.

[ElectricMaxxx]

Not only. In sandbox we create a .env.dist which should be copied and customized. In website we create one for our local development and one for production.
In general, bundles served by flex will add their own parameters when loading (an config and bundle entry and ...)