adapt docker container entry point to use alternative profiles directory

[douglowe]

The rocrate-validator allows the path to profiles to be defined (--profiles-path). Adapt the docker container so that:

1. an environment variable to contain this path is defined
2. the entry point will use this option to define the profile path
3. environment variable defaults to the standard location, if it has not been set by docker compose

Adapt docker compose script to:

1. define environment variable with this path to pass to the container
2. provide a profiles directory to be mounted in this location

Note, I might be overthinking the complexity of the solution needed. Should we assume a fixed location, and require that the docker compose will always put the profiles directory in that location, if it is passed? And do we need all the profiles in the same location, or can we supplement the existing profiles? And what happens if the directory assigned is empty or missing? These need checking out before developing a solution here.