♻️ Use `/etc/environment` with default `WS_` variables at startup and builds

[bdsoha]

Description

Generate a well-structured env file somewhere in /etc, containing all non-null default WS_* environment variables.

The values should be available:

• In bash, sh, and zsh
• During container initialization process (i.e. entrypoint.sh)
• During the building process (i.e. Docker RUN)
• Dynamic based on user (i.e. $USER, and $HOME)