Fill in `sample.env` instead of local `.env` copy

[SilasPeters]

Currently we store templates for every .env file, so that bitwarden secrets are filled in when setting up the service.
However, this requires us to maintain an up-to-date copy for every service. If a sample.env is expanded, our copy becomes outdated.

Solution

Remove all templates of .env files, and create a playbook (bunch of tasks) which copy a sample.env to .env and fill in all empty values, as defined in a variables file within Ansible. This variables file has key-value pairs which read the bitwarden secrets.

The result is not having to adjust anything to the .env, unless a new type of credential needs to be inserted - for which you need to update bitwarden anyway.