Adding environment variables for LetsEncrypt Certbot

[LedPeach]

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

I'm currently running the npm container in an SMB share drive on a Debian host machine mounted with cifs.

The issue is that certbot requires the use of symlinks which are not available in Windows and CIFS shares by default do not support symlinks.

Referring to a potential solution here:
certbot/certbot#4850 (comment)
Is there a way to add environment variables for LetsEncrypt Certbot?

I didn't see anything mentioned about environment variables for LetsEncrypt in the Advanced Configurations.
It would be great if this image could support that.

Describe alternatives you've considered

Alternatively, I could use a different sharing protocol like NFS, though it would be great to run everything with smb.