Better handle spaces and other special characters in environment variables

[CameronDiver]

Currently the support for these is shaky, and can cause some unintended behaviour, such as container restarts.

We need to find a way to make sure that a stray space in a env var value does not cause these issues.

Front conversations

[pdcastro]

and other special characters

Like line breaks: https://github.com/balena-io/balena-cli/issues/1442

[ntzovanis]

Some users are requesting enabling special characters on env vars. One example here.