Use env variables for most common configuration

[niccofyren]

When initially setting up wannabe for a local development environment there are a lot of different config files to think about, spread across multiple folders. And when using it in production it's quite easy to end up in with mismatched secrets between files or (if not careful) having to hard code configuration files with secrets into the container itself.

This tries to eliminate a few of these potential challenges by;

• Setting a few more secrets in example files to use env variables by default
• Switch migration script and config file to use .env file or current environment
• Map all known env variables to app service/container in default docker-compose.yml file

This will not be optimal for users running everything locally without using docker or similar, or that for other reasons are unable to set environmental variables and readme files have been adjusted to account for workarounds.