Set API secret from file

**Problem**

Is it possible to set the DB password and secret key from a file?
Does setting the `CUBEJS_DB_PASS`/`CUBEJS_API_SECRET` env variables to a path work?

My use case is that I want to set the key using a docker secret.
If it is not possible, I guess it should be straightforward to "define" `CUBEJS_DB_PASS_FILE` and `CUBEJS_API_SECRET_FILE` to do so.

Thanks in advance!