[Feature]: implement unused .env variables

[silksil]

Is your feature request related to a problem? Please describe.

I noticed that there are .env variables throughout the project, that don't seem te be used. This includes:

PUBLIC_STOREFRONT_API_VERSION=2023-04
NEXT_PUBLIC_STOREFRONT_API_TOKEN=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
SESSION_SECRET="foobar"
STOREFRONT_API_KEY=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

It doesn't break the app, but is confusing. Is this on purpose or am I missing something?

Describe the solution you'd like

Implement unused .env variables, remove or add a comment.

Describe alternatives you've considered

Additional context

No response