Distribute worker (conda) environment with jobs

[brollb]

It is important that each compute backend uses the worker environment created by deepforge create-env -w as the base environment (they may install operation dependencies on top of it, of course).

However, each compute backend may behave differently. For example, the "Server Execution" backend can simply ignore this file as it is executing on the server and it is safe to assume the environment has already been created. Alternatively, when using SciServer compute, the environment will need to be created each time.

Concretely, the job files should contain the worker's environment file (generated from the create-env command) and the compute backend should be responsible for handling it how it sees fit.