Menu lightning labels

[maxaleks]

Description and Related Issue(s)

Resolves #1776

Adds a new env var NEXT_PUBLIC_MENU_LIGHTNING_LABELS

Checklist for PR author

• I have tested these changes locally.
• I added tests to cover any new functionality, following this guide
• Whenever I fix a bug, I include a regression test to ensure that the bug does not reappear silently.
• If I have added, changed, renamed, or removed an environment variable, I have updated the list of environment variables in the documentation and made the necessary changes to the validator script according to the guide

[JOY]

It could be great if you guys can add an example/image for the new/changed env for every update.

[tom2drum]

@JOY example values you always can find in the ./docs/ENVS.md file
Not sure about the images though, we will think about it. Maybe we will the examples to the same file where it is applicable.