Allow more configuration possibilities for certain template projects such as PostgreSQL

What problem will this feature address?

I need to configure and fine-tune certain values, but there is no elegant way of doing so at the moment, because I'd essentially need to pass my configuration file to postgres and the only way to do it if I'm using a template project is to probably mount a volume that would contain a config, which feels a bit cumbersome. This could be workarounded by deploying postgres as a docker compose project (fetching from own repository with a configuration file in it), but this would defeat the whole purpose of a template.

Describe the solution you'd like

The trivial solution might be to just allow passing configs or common values, but this is probably inefficient because it would mean that each template project would need its own opinionated set of values.

So what I think might be done instead is to make template's internal docker compose (or whatever is being used) visible to the end user in an advanced tab (or similar). This means that for users who deploy apps or use templates and want some customization of a standard template, there would be a possibility to go to the "Advanced" tab and update things as needed.

Describe alternatives you've considered

Writing docker-compose.yml manually and deploying a database as a docker compose project.

Additional context

No response

Will you send a PR to implement it?

Maybe, need help

No files, tests, or entry points are named. Start by locating how template projects deploy their internal Docker Compose definition and compare that flow with manual Docker Compose projects; done would mean users can safely view and customize the relevant template configuration through an advanced interface.