Docker: Allow specifying storeid/storefile to create a store with a deterministic store id.

[MidasLamb]

I'm currently trying to set up some integration tests with OpenFGA (among other things). However a pain point is that every time the docker container is created I have to:

• Make a new store and remember the ID
• Upload a new schema to that Store ID
• Configure the application to use that variable store ID.

I think it would be a nice feature if (for testing) there is someway to create a store from a schema, and have it have a predetermined ID.

For me, this is akin to e.g. POSTGRES_DB env variable for the Postgres docker image.