[Feature Request] Support Setting DOCKER_MODS in Linuxserver Containers

[viveksupe]

Feature request

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

Trying to override containers to include DOCKER_MODS= but the override isn't being merged. There are multiple containers that support mods that do on persist after compose recreate.

Eg features:

• https://mods.linuxserver.io/
• https://github.com/linuxserver/docker-mods

Can future versions allow users to add these mods as Env variables or similar?